3) overusing surfaces interactions (water, grease, blood etd - same as DOS; please enough with DOS features),
I agree 100%. One of the most jarring features in D:OS games is barrels everywhere (completely out of place) and nonsensical surface interactions that transform the battlefield into a vfx mess. It can be fun for 1 or 2 combat encounters, but otherwise it's just a shallow and repetitive gimmick.
As long as they stick to the depth and complexity of the D&D ruleset, it'll be fine. This, of course, includes not altering the 'to hit' probability formula, because missing attacks isn't frustrating, it's a core aspect of D&D.
