1. Remove the insane quality variance per tile and make it so that all ore/stone/coal/etc mined on a singular tile is the same quality. The quality variation is incredibly annoying and despite the multiple nerfs you guys have done on it the variation is still very large. This doesn't add anything to the game other than having to waste time sorting everything by quality.
2. Remove boulders spawning while mining. This is just annoying and seems to defeat the purpose of select area mining resulting in you needing to watch your screen super closely so you're not getting stuck every 20 seconds. I'm not sure if this was added to counter botters but if it was it's not very good at it and encourages more botting. The only benefits I can think of to this is higher quality ore/stone when useful which wouldn't matter if #1 was implemented and of course easier quarryman/miner credo which isn't cool enough to justify the insane annoyance this causes.
3. Either remove support decaying or significantly nerf it so you basically need to mine the whole support before decaying. Like #2 this basically just requires you to watch your screen extremely closely otherwise you might get randomly koed by rocks falling on you which is the most annoying shit ever. Mining without a custom client to notify you that the support hit 25% is basically unplayable in my opinion.
4. Either completely remove the ability of slimes to spawn while you're mining and just leave them wandering caves, OR at the very least reduce the frequency of spawns, reduce the maximum amount of slimes per spawn (it can get around like 20 which is ridiculous), remove the doubling/trippling/quadrupling mechanic of slimes (annoying as fuck). Slimes are fine and can be useful if they're just wandering caves, it's fucking retarded to get 10+ spawned on you though.
5. Remove boreworms spawning on you while mining. These things have like 1500+ health and spawn in packs BEHIND you usually basically just blocking you in and ensuring you get knocked out by an annoying RNG spawn. There's nothing fun about this, it's basically just haha take a break to heal your wounds or have insane reaction time and good RNG to run away before they surround you. Them jumping out of the ground in caves at you is fine but spawning on you while you mine is cringe.
6. Not entirely sure if it works this way but it certainly feels like there's some regional ore/stone spawns. Basically you find a ton of one kind of ore in an area and none of another. It it does work this way it's extremely annoying since you need to either mine very far away from your base just to have a chance at good ores or build new mineholes in other areas which now take very long to build. Pure RNG mining is more enjoyable than regional bullshit imo. This is less important than the first 5 which are actually all complete shit imo.
It's possible I'm missing some stuff since I thought this up pretty quickly. There was a lot of really horrible changes to mining.