The number one thing that frustrates me is getting stuck in slabs, carpets, snow, stairs. For the map, I would suggest having kit players help with the map, or at least have a beta of some sort where we can say what's good about the map, and what's not.
Personally, I hate the void. Some may disagree, but void is pointless in kit. You can easily kite to a void spot and shoot people off all day. This makes actually fighting people less relevant, and makes kiting less "rewarding?" Not sure of the word to use here, but I hope that you get the point.
A more established set of rules. Right now, we have a sign board at spawn with the rules, and while this does get the point across, it's quite easy to miss and many newer players don't know all of them. Maybe a /rules with some sort of GUI, and upon your first time joining kit, you are asked to read through this gui and accept (like a checkbox) before your allowed to drop and fight.
Kits: Right now, we have 2 kits you can get by simply playing the game: revenge and juggernaut. I would like to see this expanded upon with more kits. These shouldn't be OP, but should be rewarding to unlock. Yes, I understand legendary and ancient set are attainable by playing the game, but that requires a key, and you only have a chance to get said kit IF you even have the key. Maybe make legendary kits rewards for HIGH streaks, I'm talking up to 3k, as not many people are able to hit it. Could be lower or higher, but I think it would be nice to be able to have a dedicated in game way to get them. To expand upon this, maybe loot drops/supply crates at random times (ie once an hour, for ancient, once every 3 hours for legendary) and the coordinates are announced it chat.
Crates: We get one seasonal crate, legendary, and ancient crate. This isn't a bad setup, but what if there were armor or weapon crates, or killstreak crates, or mana crates? Expanding upon this, what if drops had a star rating or rarity. For example, a player is on a 10 killstreak. This player returns to spawn, and goes to the killstreak crate. Since he's only on a 10 killstreak, he can only win common prizes (or 1 star rating), such as a gapple, pearl, health pot, etc. He eventually goes on a 100 killstreak, and goes to the killstreak crate. Now he has a chance to win up to rare items, or 3 star items. He could either win a gapple, at common, or get lucky or get a rare armor/weapon key. He takes the key, and opens up the armor chest, gets a 4 star legendary armor chest piece, with prot 4 on it. This is all hypothetical, but I would love to see this expanded upon. Make it complicated, gives players more to do.
Repair: Many players without ranks often ask those with ranks to repair for them. This makes gsets or even iron armor useless to them, as once it breaks, they risk getting scammed out of their gset by asking someone to repair, or they just let it break. Repair should be a universal perk that everyone has access to, but if you do have a rank, make it up to 50% cheaper. A gset cost 4k to repair right know. If you don't have a rank, make it cost 4k, while if you do, make it only cost as little as 2500. This would keep those without a rank playing for longer while not making the game pay2win.
Gsets: I personally feel like gsets are fine as is, and I do enjoy fighting in gset. If they were to be changed, make them more rare, or more expensive. Fire Aspect is also a problem, and should really only be purchased, not in a kit.
Punch 2: Punch 2 seriously needs to be much more rare
Anticheat/Server Lag: The anticheat is mediocre at best. I don't expect a flawless anticheat, where players are instantly banned upon joining. However, I think that regen and fly is just unacceptable. Not much of a dev, so I can't speak much on this, but I would really appreciate an anti cheat. Serverside lag, I also can't say much. However, I am NA-West, and it's pretty hard to kite when the server is busy. I have seen people in videos kite fine, and I'm not sure if it's location based, but I average anywhere from 100-200 ping.
These are just a few of my thought, others have also put in valuable input. Thank you to anyone who actually read through this, and let me know what you think, or anything that should be done differently than how I mentioned it.