Skip the singleplayer. Unless its a Bad Company style fun adventure into crazy town with funny
characters that actually fits the gameplay instead of the overly serious campaigns of linear corridors in the last two games, I would be sorta fine with it.
Focus on clear class roles. Less gadgets that does absolutely nothing like the EOD bot for the engineer, the little airplane drone for the Sniper, the mortar that never could become fairly balanced anyway for the Support, the medbag being a all-time superior choice over the medpack for medics, in BF4 except being annoying stuff. Levelcap did a excellent video a long time ago about what could be done for Battlefield by removing all the useless, unfun stuff in BF4:
https://www.youtube.com/watch?v=jTp9cnueRVY like that horrible AC-130.
Less cross-class weapons. Have each class have access to a unique set of weapons each so that they can have distinct playstyles. Snipers gets DRMs. Assaults gets shotguns. Support gets carbines. Engineers gets PDWs. Something like that.
Longer Time To Kill on weapons. Make it sorta on the range of BC2. Firefights feel way too quick and almost impossible to survive and teamplay with others. Cause the moment you ask someone to do something that requires them to stick their body out of cover, they get shot instantly to death.
Either remove the knife kill animations, or at the very goddamn least the one from the front. The one that is a sure way to get
yourself killed. Nobody except if they are braindead have failed the frontal knife quicktime event, its way too long, its always the same button after a long warning animation so you are instantly ready for it. If I make a stab at someone from the front, just make it a quick slash or something that just instantly kills them. I don't wanna get punished for actually making it to their face and be the first to stab it, or get punished that they for some reason (either hearing me or just feeling like it) turned around the instant I clicked my stabby button when going for a backstab and kills me. I got that close to them, I clicked the stab button first, I just want my kill and move on.
No more fucking Battlepacks. I just wanna get the damn parts for my weapons without having to rely on RNG. They are in the game for no other reason than to be sold anyway. Use a system like the latest Call of Duty games, give me coins or some kind of currency when I rank up to spend on unlocking the stuff I want. Its more satisfying, gives me the stuff I really want faster and lets me make actual, meaningful choices when I rank up instead of having to rely on a DICE roll (hah!) to get the stuff I want.
Map design. DICE has really fallen on its face when it comes to this lately. Many maps feel messy with no clear design that makes them most of the time terrible to get through. No clear routes, often full of annoying places people use cause it gives them a superior advantage to shoot everyone anywhere. While I for instance have enjoyed fighting for once in major cities, having people walk around on the roofs and snipe you constantly have been a major frustration. The only recent map I have really loved and enjoyed is the newly released Dragon Valley, a 10 year old map from BF2.
Remove jets. They do nothing really except being either really annoying because its hard as balls to shoot them down from the ground or they are constantly locked flying in circles with other jets cause they try to for 5 minutes get a lock on each other, and when they do, flares, restart, another 5 minutes of flying in circles.
Also no more modern/current/1-year-into-the-future warfare. Its been done. Its boring as fuck now. Either make the 2142 sequel people have been asking for that could give unique looking and functioning weapons (machineguns that stabilizes after being shot for a while, portable shields, autonomous drones, GIANT STOMPING MECHS), gamemodes (Titan Assault etc.) or just do WW2. Heck, even a cold war gone hot setting ala World in Conflict would be fucking awesome.
Rushing up the beaches of San Francisco or Los Angeles. Fighting in the streets of lower Manhattan. Combat in the cold woods of Norway, Sweden, Finland whatever Scandinavia around some villages. Heck, make a map in Stockholm already! You live there DICE! Just peek out your window, take a photo, paint in some Russian and Nato forces fighting in the streets and work from there! The potential is great in this. Can even give the Commanders some really fun little toys to drop on the enemy instead of just missiles like a Fuel Air Bomb.
Think of how that shit would sell the Frostbite engine being rendered in realtime. Think of the fun for players instead of just being instantly killed by a massive explosion out of absolutely nowhere they would first see a dangling package being sent from the sky, followed by darkness by the giant cloud of fumes for a few seconds before the massive shockwave hits them as it lits up.