Fleshing out the melee combat and adding a co-op Dinosaur Hunter mode should be obvious innovations for the sequel.
I'm not sure I want more melee in this. I guess the most I want is more defensive options other than rolling. So maybe a block or parry of you timed it right and you can get a 1 or 2 melee hit. But I'm not sure I want this to be monhun/souls close combat focused game.
What I want is to explore more weapon and trap options. Also more interaction with the world. Like if a robot is on water. A shock bomb or something should electrocute them too unless they're immune to the element. Also skill to allow you make huge trap like the log trap you see in hunting trial. I want to be able to make my own trap like that.
All robot ahould be mountable with ability to give simple command.
Aerial combat by riding stormbird or something similar.
Grappling hook as part of your traversal option instead of just contextually used to drop down from high places.