[Segment 2 of 4]
Bugs, I know I know, this is a QoL thing, but these at least have to be mentioned. A fair few of these ascertain to co-op creative in their usage.
With the RR tesla coil, you can have it charge up an attack at someone but then change team (to theirs or neutral) and still have it do full damage when it fires (if your target is still in range). This can be used to heavily grief other players who are doing nothing and can't do anything but run, which is not always the case...
Another very annoying issue with the tesla coil is that it creates a massive amount of lag when it doesn't have enough power to taze something, and thus when someone spawns in their giant tesla brick and inevitably runs out of power, the entire server will start dying.
With any projectile weapon (sticky bomb launcher in particular), you can shoot a player and swap teams before the projectile hits/detonates, and it will do full damage when it does. The main usage of this is to get into a fast, agile tech and run at someone, fire off your stickies, run, and then swap teams to do a massive amount of damage at no cost. Again, this can be done with standard weapons, but the sticky bomb launcher is the most prevalent and annoying.
Going above 5000 ft will make your tech invulnerable to any damage and any physics, meaning you can sit up there and no one can do anything to you. This is absurdly annoying when said tech is an orbital strike cannon that you can do L I T E R A L L Y N O T H I N G to except threaten to kick, which really should only be a last resort.
Unofficial mods. I'm looking at you, miscmod. You can activate the client-side mods whenever you want, and it's very annoying. Context being that you can go several hundreds of thousands of m/kph and the host can't do anything but threaten to kick, or get a minor 5-10% speed boost that you can't even notice. Target lead to, but come on, who doesn't have this one on already? At least the nice part is that the host controls water height.
In deathmatch, there is a serious bug where some players simply cannot hurt other players in specific. This is the main bug that kept me away from it, and why I don't have much to say about it.
Being hit by missiles (including your own, contact that is) will cause your tech to jitter. By this I mean that your tech will essentially stutter, which can make flying planes with a few avalanches very uncomfortable, and can mess up your flying if it's severe enough.
When you pick up a block and swap techs while it's still doing its animation, the block will become a ghost block that you can't remove. This bug is annoying when a tech gets destroyed and someone goes to clean it up and they don't wait long enough and you have a big mess.
Co-op Campaign
Furnace generator. Its single input causes far less desync than what base GSO delivery cannons can do (literally just having two causes massive issues if you're not the host).
On the topic of power, I see no reason why we can't have the geothermal generator, I mean, come on, it doesn't even use chunks.
Maybe increase the sell price of blocks from 1/9th to 1/6th, because spending hours grinding missions is only entertaining for so long.
One issue with co-op campaign is that it's very easy for you to lose all of your blocks. Ways include players dumping them all on the ground, players voiding your entire base, players building a horrible tech and then immediately dying with it, players wasting all your money on useless blocks, and more. I've personally had to sell 3 big berthas because people would make a platform tech and drive straight at an enemy because they think it's their own little creative playground, and then proceed to immediately leave. What do I suggest for this? Adding a rep system. You can either leave a good or bad reputation on a player, and it can be seen through something like the player menu. For example, if you think someone builds really nice techs, you can upvote them, and when they join another server, the other players can see this, and give them a bit more respect. Naturally, there will be people who attract dislikes, such as cab bombers (maybe there could be a system where only players with a certain rep can join). You would know to avoid or be cautious of these people from the community's opinion of them. One thing I would suspect is someone like me also naturally attracting downvotes, since I'm usually pretty harsh and swear out children, but it's usually because they're scummy in their ways and that I play the game to beat people up. As a possible counter, you can limit the daily amount of votes that a person can give, like World of Warships, though there will still be those people who'll downvote anyone who they don't like because they don't like them personally, but it'll at least be somewhat limited. (this kinda expanded past co-op campaign, but you get the idea).