I think everyone that is literally asking for stuff to be LOWER resolution is insane. The stalactites and stalagmites look good, and I sincerely hope the development team don't listen to the insane people that think they're "too high-res" for the game.
Bundles are fantastic, and will make working on a lot of things like farms easier. People also apparently aren't thinking about things that stack in low numbers (or don't stack at all, such as enchanted books and tools). I'm going to be carrying at least 5 of these at all times when the update rolls out.
Archeology is quite strange and I think the development time spent on it could have been put to substantially better use. This is the cave and mountain update, and instead of giving us new tools for mining faster/more efficiently, they give us a brush to mine blocks more SLOWLY, for USELESS decals for ugly giant pots? Are we going to be getting cobras revealed later or something so the pots can be used as homes for them? Are the pots going to be useful for ANYTHING? This is going to be just like the update aquatic with boats. If we don't get new mining tools now, in the Cave Update, we're never going to get them and that's horrible.
I agree with whoever mentioned how much more GOOD content the average modder can put out than an entire development team in a multi-billion dollar studio. These updates with this scale should be coming out multiple times a year, not once.
I really hope amethyst crystals aren't ONLY used for the telescope. I'm holding out hope that you'll be able to make some new tools with them that can mine faster than anything else or have some other kinds of special properties. Having a gem resource that can only be harvested from uncollectable geodes underground would be a ridiculous waste if the crystals don't have some powerful purpose, and telescopes ain't it, chief.
The actual cave and mountain generation looks significantly better, but the bar hasn't exactly been set very high on that.
I like the concept of the mountain goats, but at the same time I have to wonder if they're going to make mountain traversal and/or basebuilding too much of a hassle to bother with.
Axolotls being giant waterdogs is hilarious and I want them yesterday.
The new redstone plants are so awesome that I think even I will be able to build some cool (and most importantly easy) redstone devices that serve a purpose now. Redstone is the one area of the game I'm not at all fluent in because it's generally so complex and time-consuming, not to mention bulky and ugly, for so little reward. These new wireless redstone plants look to change that.