Both of those seems pretty cool, I would also think it pretty sweet if they added a few hidden/explore areas with the glide (I'm not suggesting every zone, but to just make something extra to come back around for).

The swimming bit could also be used to unblock a few of the ankle deep rivers in the shroud area, the invisible walls on those specifically trigger me lol. I get that not all of the swimming areas would work because some would require more detail in areas but with your limitation of no diving I can name a few sets of water that have full detail on all surroundings and are just walls because we didnt have swimming previously.. I'd love to see those go~