Mortal Kombat 11 was many steps in the right direction, but also had huge missteps.
The dial-a-combo system absolutely needs to go. It sucks, it's always sucked. The idea that some combos need to be rapid fire input to even work is bad design. You should be able to react, cancel, and more strings should divide into other variations with separate endings.
The custom variations are terrible. The variation system in general needs to go away. Just make one good, complete version of each character.
The game had a huge issue with the krypt and unlockables. It actually killed the game for me. You spend so much time using AI bots rather than playing just to unlock stuff, and then you have to farm for WEEKS just to get currency for a chance at good items from the loot shrine. Honestly, take it a few steps back. Have things unlocked in story mode, have a simpler krypt where other things are unlocked (Think Deception simple), no loot shrine, and let people play. Also, arcade mode and online matches should give much better rewards. Having AI play towers for you should not be the only feasible way to get things.