I really like the idea of the caves and cliffs update, but there are a few problems that I think could be fixed.
I don't really see the point of archeology. I understand that it's supposed to reveal the history of the world, but honestly, it just doesn't feel like Minecraft. It feels unnecessarily complicated and doesn't really add anything to the game. I think the main problem with it is the brush and the shards or the pots. I agree that it's cool to find abandoned excavations sites in your world, but I think that the brush is a weird way to uncover the items. I know that it's accurate to real-life archeology, but it just doesn't feel like it belongs in Minecraft. Maybe instead of brushing for artifacts, the player can use a shovel to dig around the site, and crystals or copper are more likely to generate near these sites. This is a good way to incorporate the new ores and remove the complications of tons of new kinds of shards and the brush, and players already know how to use a pickaxe and shovel, which removes the possibility of the player being confused about how to excavate. I'm not sure if the clay pots have a mechanic or if they're purely for decoration, but either way, I don't really think that they serve much of a purpose.
I actually think that bundles are a good solution for storing extra things that you find while mining or exploring. The one problem is the way that the UI displays the items that are inside the bundle. It seems that the items are just all clustered around when you hover over the bundle. I think this is a problem because, in the example video, there was a bundle with flowers in it. There were so many different types of flowers and they were all scattered around the place, so it was hard to tell what types of flowers there were. Maybe instead of clustering the items to make them hard to see, the items are in a row and similar to a chest, it shows the item and also how many there are. This makes it more organized and easier to see so you know what is in your bundle.
The telescope is pretty cool, and I think that it is an interesting way to put the new ores to use. The one problem is how detailed the circle looks when you look through it. I know that the telescope can be subject to change and that this might just be a temporary style, but I thought I should point it out anyway. Minecraft is known for being blocky and 16x16, but the circle around the telescope looks a bit too detailed. I just think the circle should have less detail, which will make it look more like something in Minecraft than something from a texture pack.
Stalactites, Stalagmites, and Spore Blossoms
I am putting these all together because I think they should all be changed for the same reason. I think that they look a bit too detailed. In the case of stalactites and stalagmites, when you look at them from far away, and even when you're only around 10 blocks away, they look too much like actual triangles. I think the cause of this is that the details are in 16x16. What I mean by this is that near the top, it goes inward by 1 pixel for each part of the slope. This makes it look too much like an actual triangle. I think that to fix this, they should go in by 2 pixels and also the slope should start closer to the bottom, maybe around half way through. Also, I think that since they're 2D like flowers, they don't look as blocky. What I'm thinking is that the stalactites and stalagmites can be reworked to be more like an end rod but it's way longer and it starts out as a full block and gets more narrow towards the top, 2 pixels at a time. This allows you to still keep the idea of stalactites and stalagmites while making them look more like they belong in Minecraft. Of course, another way to fix the problem is to just reduce the amount of detail in the geometry of them while still keeping it 2D to be less resource-intensive. I think that either way would work fine.
As for the Spore Blossoms, they have the same problem of being too detailed. However, the solution for this one is quite different than the stalactites and stalagmites. The reason that I think they look to detailed is again, the details are in 16x16, which does make the diagonal lines look smoother, but it also makes them feel less blocky. I think that the solution for this is again to just make the diagonal lines 8x8. But honestly, I think the diagonal lines will be fine as they are right now. The main problem is that the flower part of the Spore Blossom folds in to look like a bowl. The problem with this is that the flower curves at a slope. There currently aren't any slopes in Minecraft other than minecart rails, but minecart rails look fine because they are at a 45-degree angle and are connected by blocks. The Spore Blossom has neither of these going for it. I think that the fix for this is to make the flower completely flat and just curve the edges in by 90 degrees. However, this makes it look a bit too flat, so a better solution is to keep the slope, but instead of making it a normal flat slope, you can make the slope more pixely. This will require the flower to no longer be fully 2D, but it will make it look a lot better. It's kind of hard to explain, but basically, instead of making the flower a normal slope, you can create the slope effect by making the flower be flat for 2 or 3 pixels and then make it go down 1 pixel, and continue this until the end of the flower. Again, it's really hard to explain, but I think that you guys might be able to get the idea. I would be willing to create a 3D example if it's still confusing.
This one is more of a suggestion than criticism. I just think that adding frogs alongside axolotls will bring a lot more life to the lush caves. The point of the lush caves is that they are supposed to be filled with life, and the plants really help with that, but if you can only find 1 kind of animal there, it kind of ruins the illusion. It just seems weird that there are all sorts of cool and extraordinary plants in the lush caves, but only 1 animal. The new animal doesn't need to be a frog, but I think that frogs would be a really good fit because they are small so they can fix in narrow caves, and live around water and vegetation, which really fits the description of the lush caves. Also, let's be real, it would be adorable to see frogs hopping around and hanging out with the axolotls. Another reason why I am suggesting it is because last year, frogs were promised as a part of the swamp update if swamps got picked. I know that swamps didn't get picked, but based on the fact that you guys were planning on potentially adding them with the swamp update indicated that you are willing and capable of adding them.
I know that this post is really long, but if you look back, the things that I am pointing out and suggesting are pretty basic. In essence, I am just asking that the new update should feel more like Minecraft. The ways that I mention to fix this is basically to remove unnecessary complexion from the current archeology and bundle systems with something more traditional, and fixing the new art to look more blocky and more like it fits and belongs in the world of Minecraft. As for the frogs, I just think that they would be a perfect fit for the lush caves because frogs live in that kind of environment in real life, and I think that the new lush caves biome is even a better fit for frogs than the swamp.
I and many others have wanted a cave update for so long, and I am so incredibly excited that it's finally here. I love what Mojang has done with this update and with the game. I am so excited for the first snapshot and will 100% play it the day that it comes out. I know that Mojang also cares a lot about this update, and my suggestions are just essentially just trying to point stuff out to them so that they hopefully fix at least some of these small issues to make the update even better than it already is, and to make all of the content feel at home and a fully functioning part of the future of Minecraft.