Everything Skull Girls had, from the ability to choose your frame delay when going online to being able to skip super flashes, have safe states, turn on hitboxes, being able to see whose in the life lead, live frame data, ect. I also want to see other things from other small indie games implemented like Rivals of Aether's button check system in the character select screen with being able to play with your character in a small box below without interrupting your opponent to make sure your buttons are set.
NRS has done a good job with adding in a lot of QoL features already that I wish other games had like instant rematch and online character select screen that many japanese FGs dont have.
I shouldnt even have to get into the talk of having good netcode because its 2019 and not everybody has a scene, has the money or time to get to one, or wants to go. While a lot of people may not accept it, online is the future of fighting games and considering that fighting games require precises inputs I should expect without question for them to have good netcode. People giving X reason for why their game doesnt have good netcode are part of the problem and only hurt the FGC and the genre as a whole. If you dont like the constant complaining of better netcode for ALL fighting games then once again, you are part of the problem.
Its mostly the Japanese devs that are not willing to change and I hope something shakes up their entire market to force change. Part of the reason why I am excited for that Riot fighting game I heard about and the possibility of it having a good amount of the basic things that I mentioned.