Can't make steps, piston, item frames, redstone torches, enchanting tables!? so you can't even get the achievement that's made for crafting one.
Something happens when the world does a mysterious refresh while you are playing and knocks previously generated flowers and planted pumpkin seeds.
Something happens when you travel long distances, grass and sometimes tree leaves to the sides of you break for no reason. Didn't even look or target that way.
Also, when you travel long distances and like try to climb a hill, and pick up the dirt, it's not in your inventory for like 45 seconds.
F3 does not activate coords, but F5 will change your view.
If you open a chest with an egg equipt, you accidently throw it.
When you clear your hot bars to harvest wheat and plant seeds, the wheat hops from your inventory to your hot bars where you wanted the seeds to go.
Lost progress on exit. Quit to title didn't save?
Spawners don't have monsters.
Opened a double chest and it was a single chest.
Iron Golem despawned in my house.
When you return to an area, fenced animals will lose their coordinates, and spawn outside of the fences.
Rotten Flesh is dog food, but you can't feed it to dogs.
The lag that everyone experiences in the nether on the xbox 360 and the PC version, makes you auto-run in the nether.
Never seen a gasp in the nether. Over 10 hours played in the nether.
Today the skeleton spawner worked!
Apples don't drop from trees, so you can never cure a villager.
Never ever ever seen a cat. Another achievement gone.
Found a village! It was empty.
If this game was on Steam, you could get a refund if you don't play for 2hrs.
I'll try to answer most of your questions. Before I do, you should take note that the Windows 10 Edition is a port of the Pocket Edition to run on the Universal Windows Platform. Put simply, it's designed to run on all devices with Windows 10 wether it be a phone, a laptop, a PC, the Xbox and currently unreleased devices like the HoloLens. You have significant restraints on processing power so that should answer why it's a port of PE and not PC (there are lots of other reasons too).
Can't craft stone-related items
In PE, there is a block called the "stonecutter", see the wiki page here. It allows you to craft stone-related items like stairs. Tommaso, one the developers decided to to a poll on whether to keep the item (emphasis on MCW10E) and the results were to keep.
Can't craft redstone-related items
Redstone is not yet in the Pocket Edition, although it will be soon.
Can't craft other items or blocks
See a list of blocks and items that have currently been implemented in PE here.
Can't use F3
There is no debug menu for the Pocket Edition. F5 exists as an alias to Options -> "Third Person View" if you connect a keyboard to PE or use the W10E.
Projectiles being used when opening containers like chests
Known issue with PE.
"When you clear your hot bars to harvest wheat and plant seeds, the wheat hops from your inventory to your hot bars where you wanted the seeds to go."
I'm not sure what you mean by this.
Lost progress on exit, blocks not being collected or areas on the map re-rendering, entities being forcefully despawned and game crashing
Your processor is not capable to keep up with the game, which can cause all of the issues you gave. Close any other applications that you may be running that may be deferring the game. Give us a Task manager log of when Minecraft is running and also give us a DxDiag log.
Lag in the nether forcing sprinting
Cannot reproduce on PE or the Windows 10 Edition. Probably due to the above.
Ocelots and Ghasts were added in unreleased 0.12.1 testing versions, the Windows 10 Edition is still on 0.12.0 currently.
Can't find certain biomes
See a list of biomes in the Pocket Edition here. Both Desert and Mushroom biomes exist.
Refunds are generally not allowed on Windows Store apps (just like Android/iOS) unless you wrongfully purchased the game. To be specific, were misled, unauthorized or paid for the Windows 10 Edition even so you can get a copy of it for free if you have the PC version