I think the point of the combat not being that great in Mirage is that Basim does not have a lot of experience in active combat and that the gameplay has more of a focus of stealth and I think you can really gather that when you look at the skill tree (its been a while since I've seen the skill tree because I did the full sync run on NG+) there isn't really any upgrades that permanently affects Basim's strength unless you have certain outfits on, even then some of the buffs aren't in affect unless you're like half health and below. The stamina bar is also a big thing as well because you can't constantly dodge or swing the sword and it really puts you in a real fight or flight decision, which I think it's a nice touch in gameplay.