I keep trying to write the response to this in some sort of "MK2/UMK3 + modern stuff", but honestly when I look at it, that boils down to "just MK9 that works with some of what they've learned added".
1. Fix the shit that's just flat out not working. So many characters in that game literally do not function or have moves that just don't fucking work. It's a shame though because the "theory" of what they should be doing is actually extremely flavorful, cool, and varied.
2. Balance the top to some extent. I think kabal should still be good, but yeah he's got to lose some shit(locking it behind meter would do a lot). Ditto with kenshi and several others. At the end of the day I should still hate being stuck in block stun vs Johnny, but it's way way too much right now and makes it harder for other kits/strats to work.
3. Modern netcode.
From there my other wishlist items would probably be:
1. Rework meter. Breaker at 3 (with mandatory cyrax tweaks). X ray's removed/reworked. "supers" that finally do things besides damage. Give the game the sort of design space where you could have rashid tornado or some full screen fireball or whatever. Not just hit into canned animation
2. Some sort of KB addition. D2's are iconic and landing one on a huge read SHOULD lead to some major call out moment at the minimum. From there I think the bones of something good exist in MK11 in that it should be conditional stuff, but not "use move X time". Counter hits, anti airs, using after another move (say classic raw spear into d2 KB's etc). Basically do the same weird conditions you were doing with brutalities, but mid match. It's such an MK thing and it's perfect, so i'm shocked they just threw it out with 1.
Hell i was looking around at footage to get my thoughts together and I do think Tom already touched on a lot of it:
I really think that's it. For the casual side just do a decent story mode. I think treading new ground is fine but you need half decent writers/need to let them do their job and not funnel them into "nobody dies and also have you heard of this marvel thing?".