I miss: Learn by doing as the current magazine and perk system is complete trash, I miss sandbox elements like being able to make a underground base if you wanted to being viable. I miss the old gun system as it was nice finding a gun with better parts to upgrade the gun you have. I miss the garden hoe was funny how tfp was like "It won't work technacally to hoe the ground like you used to so you have to use these stupud farm plots" 2 days later modder releases a mod that lets you hoe the ground TFP said was techancally impossible to do that works flawlessly. I miss proper progression, or well, I should say the game never had any proper progression of the biomes ever. People don't leave the forest because you can craft pretty much every item in the game without ever leaving the forest, THATS the progression problem, and why no one goes to other biomes, the 2.0 update is just stupid as its going to make it even MORE annoying to go to other biomes so even LESS people will bother now. TFP needs to redo the entire item/crafting system and give each biome its own unique resources, that can only be found there to make that tier of gear, however you also have to balance this so you can't just run into wasteland on day 1 to get the top materials and make the top gear. I also miss the hatchevator, that thing was great for underground bases, but sadly the bug that allowed it to work was the same bug that let zombies pass thru solid walls so it was a unfortunate bit of collertal damage. I also miss water jars, as its stupid your char basically eats the jar after you drink from it and that it cannot be reused. I also miss the game being fun, the current perk and magazine system is aweful and just take alot away from the game, especially weapons being stat locked was a big nono, many general perks like miner 69'er, motherload etc should be uncoupled from stats and added to a general perk pool, which is something 2.0 is going to have, we can only hope they put general use perks like that inside it. The game is not a rpg its supposed to be a sandbox and it currently has way to many restrictions on things.
Other issues is some stats are just a waste of points because the perks it has in it are very niche or not very useful. Like Str currently has some of the most useful perks in the game: miner 69'er, motherload and master chef as these perks are always useful. As well as solid melee choices and iirc shotguns are also str.
As for things I don't miss: well there isin't much here, before they put it back I would have said the burnt biome, as even today the burnt biome serves no real purpose and has no real reason to exist even in 1.3. There is nothing unique to that biome, and no real point for it to exist, kinda like the plains biome, it never really had a purpose.
What the game needs: redone progression and items and crafting where each biome has its own tier and loot/crafting recipes, and you have to make stuff from the previous biome to be able to access the next safely, to prevent people from just going there on day 1. EG Wasteland could have radiation pollution and you need to find something in a lab in the snow biome to gain protection from that for entrly level area's and then to go deeper you need to upgrade that protection with materials from wasteland. Look At Valheim as a prime example how to do biomes right. You try to go into the snow biome in valheim without proper protection from the cold? your char literally dies in like 30 seconds. All you can do at first is very short runs into it, to try to kill enemies for their skins to make proper anti-cold gear. No one goes out of the forest really in 7dtd because there is 0 reason to, you can craft every single item in the game except one without leaving the forest, the only item you can't is gas because oil shale only spawns in the desert, but one mining trip to the desert is prob all u need for an entire run. There is just no incentive to go to other biomes as there is no real need to. Sadly TFP for some reason does not seem to realize this core problem and keeps refusing to fix it. Making the biomes more annoying to go into is not going to get more people to go into them, its going to do the opposite and make even less people wanna bother.