If you remove the shower door panels, you should also remove the track and repair the walls. As a buyer, I would prefer the frosted doors. Leave them.

I personally don't like the doors, they look a bit dated. But... if you're sprucing up to sell, not sure it's a cost I'd take on - as mentioned above, you'd have to repair the walls once you remove the doors. New buyers may decide to do a full reno anyway.

I'd leave them and let the buyer decide. replacing them with a curtain is easy enough that I doubt it would scare off any buyer. Besides, they might want to keep them. frosted doors are not super trendy, but these particular ones don't look bad either -- they don't have brass tracks or designs on the glass. let the next homeowner decide if they want to change them out.

give them a good cleaning and leave it. changing that one aspect won't do anything for the overall look of the bathroom.

Thank you!