I use a cover on our 96 Southwind. I've never had a problem with sharp edges. I have found that the wind is your enemy. Secure the cover well. And I have had no problems with the cover rubbing the paint.
Steps, gutter extensions, door stop, bumper ends, antenna mount, etc all get protected when I cover. I use pipe insulation to protect against the sharp edges.
I covered my rig for the first time this year and I used swim noodles to put over the radio antenna and tv crank up antenna. The Adco cover came with pads to put over the four corner rain gutters and four additional pads with adhesive backing that I used on the slide out toppers. I'll know how I did in Spring!
I mostly pad the gutters. Nothing else on mine is sharp enough to cause a problem. Don't overtighten the straps or you may get rips at the lower corners.
I don't worry about sharp edges with our ADCO with TyVek cover. So what if there is a small hole in it? Its for protection from the intense Sun and Snow up here in the Rockies. I'm on my third year with this cover, and any holes are covered with Duct Tape. It worth the small work installing this cover, because in the Spring, I remove it and marvel at the clean and perfect paint and graphics that have been protected during the harsh Winters here.