Alright I'll keep it short, there's several things the entire community is aware of in terms of gameplay.
However, something that really needs to be updated is custom practice. This is very niche in the grand scheme of things but it's helpful. COTW is def a cool mode but you can't manipulate it to your liking for practice.
I think we should be given more freedom to modify the practice specifically to what we need to work on. If Joe wants to work on a high and in fastball, let Joe program the CPU to to throw high and in fastballs and let him loop it so he can take a thousand swings if he wants to. This is something the competitive crowd from the community would appreciate tbh. It's a waste of time to take entire at bats when perhaps you're trying to work on a specific facet of your hitting game instead.
Also, making it so that you load into custom practice and the entire pool of players/rosters are available to be spawned into the game, would be a convenient tool to have from a UI standpoint.
You can also make custom practice more interesting or fun if desired, perhaps take a look at the batting mini modes from 2005:
Just a suggestion, I never make threads but it's something I think would make lab time more efficient. Idk if anyone else would even care about this but I figured it's just a few tweaks to an already decent mode.