I could go for an idea like getting an extra Skill proficiency when proficiency increases to make up for the broad skill gap between Bards/Rogues and everyone else, but by and large, I love the leveling up system here. I'd rather take 5 minutes to finalize my abilities and then go off running to use them than leveling up being its own goddamn ordeal. Even accounting for D&D ostensibly being a power fantasy, what I've heard about 3.5 levels making characters that were either unplayable or broken seems like, idk, really indulgent.
Saw my group play thru 3.5 and now 5e and they really prefer the 5e. they didn't mind 3.5. they have played tons of system since 1e. But, across the board they find "fit to character" a bit easier to get to in 5e and not so much a "construct for power and prerequisites from day 1 to 20" seemingly mandatory vibe coming from 5e.
Some of my guys are the "constructor kit" guys but the majority prefer the quicker "level up doesn't take long to do and get playing" even if the levels come slower here and there because of how we play.
Some have expressed an eagerness to try my next game change-up: We will only level at odd- levels. All the pacing rates etc will stay the same but when you are @3rd you will stay @3rd until the point to level to @5th is reached - then you will level for both 4th and 5th at once. (This is to give an even longer time to play thru your "new stuff" before having to work in a new batch of "newer stuff" and make each "level-up" seem even more dramatic.) less re-work more in-play.