If you can go without it in your world, and still beat the game with ease, it's unnecessary.
These blocks do have various uses in the game that benefit you, directly or indirectly. I'm not saying that they should be removed, they're interesting blocks with various important functions, but they still fit the definition.
If "unnecessary" Is something a player can easily go without and have a normal game, then the following is unnecessary:
Heart of the Sea
Arguments like these are always so pointless because A) it's using a contrived and strawmanned definition of the term that I never utilized--I purely said the word "unnecessary" with no elaboration on what qualifiers I use to determine whether or not an object is indeed unnecessary, B.) it's whataboutism that tries to argue that one bad addition to the game justifies another, C) it's usually misapplied anyway, and D) even by your definition, it rests heavily on subjective interpretations of what is vs isn't "a normal game."
For example, I can argue that a normal game is progression toward fighting the Ender Dragon while maintaining as minimal investment as possible--for example, if I don't need to engage in trading with Villagers or mining for Diamond, since neither of these are strictly required to beat the Ender Dragon. Iron works fine, Nether Portals can be cast, and there isn't really anything essential that Villagers provide for killing the Ender Dragon... but, you might argue a "normal game" is something different, and atrigormortis and eiche_brutal might argue something different. A "normal game" really depends on the person because Minecraft is so freeform and adds in a wide variety of features so you can create your normal.
Nails are unnecessary in the sense that there is a perfectly plausible alternative using items already in the game. That's the point of saying they're unnecessary in this context--they're adding a step (and, realistically, a full mechanic) that doesn't need to be added since there is an already-existing alternative using an existing item (Iron Nuggets) that has the ability to logically function in the same role as Nails. But... that's also why I said in my first post on the thread that Nails could be an option if they had more functions for which Iron Nuggets simply would require too great a logical leap. Then, sure, you could justify adding in Nails and also using them to craft reinforced planks (I still wouldn't use the mechanic you suggest). In absence of that? No dice.
Has 2+ Blocks of coverage in the event of a blast. Reinforced beams can only cover one block, themselves.
With the exception of copper nails (which I agree on your point concerning them), they are VERY basic to craft and many can be crafted from only a couple of logs. Beams require a plank, as well as the ability to get iron before crafting them..
1- Per your suggestion, they would require Copper, which according to the devs is about is common as Iron. Thus, I don't think it's a strong argument to suggest that it's an unreasonable stipulation that players obtain Iron, since it sounds like this will pretty much place the same burden as obtaining Copper
2- I don't think the 2+ coverage idea is very good. It should be one-to-one IMO, but even if you insist on the 2 blocks coverage, there's no reason that Beams/Reinforced Planks (whatever you prefer to call them) couldn't also provide that function
3- Making Wood blast resistant is a pretty good perk. There should be a non-negligible degree of investment required to do that. As such, crafting them should be semi-expensive relative to the base component--this reasoning is also why the 2+ block coverage isn't good, because that leads to a massively reduced resource investment cost. Keep in mind that cosmetic and functional upgrades to most blocks are not cheap--torches to lanterns require four Iron Nuggets, which is twice what 3 Beams/Reinforced Planks would cost. The 2 Iron Nugget/6 Plank cost is honestly pretty dang cheap by comparison.
How many diamonds have you used in your current world? Divide that by 3.7 to get how many chunks you'd have had to mine out to get them, a chunk being only 16x16 blocks; 160x160 blocks = 100 chunks, 2048x2048 (a level 4 map) = 16384 chunks, 500,000x500,000 = 976 million chunks - that's over 3.6 billion diamond ore!
Also, the impact of adding more ores is quite insignificant and they will not displace existing ores if they are generated afterwards (aside from minor overlap along chunk borders since most veins are 2x2 in size) - even at layers 5-12 only around 3.3% of all blocks are ores (this seems rare but when branch-mining you can expose multiple blocks per block mined and veins are usually multiple blocks; the Wiki says up to 1.7% of blocks can be diamond, compared to an abundance of only 0.12%; likewise, caves expose many blocks), and they could always increase the amounts to offset this, much as they increased the amounts of all ores in 1.8, possibly to offset a reduction in caves (a 20% increase in ores means that they could add something that displaces 16.6% of blocks (1.2 * (1 - 0.1666) = 1) and there would still be as much ore as there was before 1.8):
This is from before 1.8; ores are about 20% more common in newer versions:
Also, this is a chart of ore distribution in my own mod, which is similar to versions prior to 1.8, aside from changes to cave lava level and the ranges of rarer ores (7 layers lower), and more lapis below layer 3 (along with amethyst this makes branch-mining below lava level more attractive). The addition of new ores (amethyst and ruby, the latter not shown as it is biome-specific) have no impact since they are generated afterwards, nor is there any significant impact on the abundance of amethyst due to being overwritten by ores generated earlier (it is 1/8 as common as diamond above layer 2 in terms of actual attempts):
These are the results from an actual world, 18687 chunks between layers 3-62 (excluding the deepest two layers which have more amethyst); redstone, which generates before diamond, is about 8.1 times more common than diamond (expected is 8), which implies that 1.25% (8.1 / 8) of diamond is being overwritten; likewise, redstone is about 66 times more common than amethyst (expected is 64), implying that about 3.125% is being overwritten (by both redstone and diamond), amounting to a loss of 3 ores out of every 100 that would otherwise be generated - note that these are within the layers with the highest overall ore abundance and the Wiki says that copper is as abundant as iron, so it will have less of an effect than redstone:
I'd rather that newer ores not displace any existing ores at all upon new chunk generation, this is one of the reasons why the game is in need of a cave update that includes modifications to the Y coordinate down, increasing the thickness of the terrain below 0, moving both the bedrock and void towards somewhere negative 2048. It improves the mining experience and it doesn't sacrifice anything important on people's worlds.
for 3 or 4 players 3.6 billion diamond ores running out would be impossible, especially if diamonds were then multiplied by fortune pickaxe.
but it is still possible to mine a lot of diamonds, especially if they are like you, collecting stacks of diamond blocks in chests
1 chest full of diamond blocks = 27 stacks of diamond blocks
27 stacks of diamond blocks = 162 stacks of diamonds = 162 stacks of diamond ore without fortune pickaxe used.
each stack of diamonds or their ore variant equals 64 which makes it 10,368 total diamonds if my math is correct.
Divide this number by 3 and you get roughly about 3,322 pickaxes.
So on a server with just 3 people you can share these and get 1,107 pickaxes each, without mending it would still take you a long time, still possible but this amount of pickaxes would last months of real life play I'd imagine, factoring rest, meals and what have you in between.
But if you were sharing these with 100's of people on a large server, they wouldn't last very long, and the more people you have on a server the more likely it is to be griefed, even if whitelisted, so it is probably not a good option if you've got a lot of work which you'd like to keep. But let's say hypothetically for a moment, you were playing on this kind of server and you and friends were all very cooperative and didn't grief because you all knew it was better for everyone to work together for a common goal, therefore work becomes much more efficient and less time consuming, 1,107 pickaxes wouldn't last very long in this case with a 100 people or more and you can destroy them in less than a full week of gameplay without enchantments or if you did something silly like dropped them in lava.
What I'm saying is, it's a good thing Minecraft worlds on the PC version and bedrock edition are so large, because if they weren't, resources would be too scarce to the point where friends would end up having petty arguments over who gets what. Such dramas should not happen, especially not over a video game, and this is why I hope Mojang would patch the problems involving the far lands, so people can keep playing on the same worlds indefinitely no matter how many players were invited to the server, because there is always space for people to use and there is no point in fighting over it.
Nah i love sponges for getting rid of water where i dont want it to be at like huge lakes n such
I use lanterns because they're easy to make and because they're common, they may end up replacing torches as the cheap permanent light source someday as allegedly was the original intent of the devs, but that's okay, it's not as bad as I thought it would be, and iron nuggets are used for crafting the casing of the lanterns instead of ingots which allows us to spread the resources out even further. The only disappointment with lanterns I found was their soul lantern variants, which have poor luminosity compared to the regular ones so it is not worth using them in the overworld in my book.
I don't use sponges currently but that doesn't mean I won't find a use for them some time. It just means currently me and friends do not have them, but it's possible. Say if I want to build underwater dome structures, sponges would help me quickly clear away the water from the inside of the glass dome under the sea.
I cannot find a practical use for the nail suggestion though, if blast resistance is the concern I'd just use harder materials like stone or obsidian, it's not that big of a deal to me. Perhaps others would like to use them, but nails would need more of a purpose than this in my opinion.