A little confused -- the bottom one is the current arrangement, with a large vanity and a small shower? And the top one has a long shower and a small vanity, with space wasted in the corner? Could you slide the shower up closer to the sink and put a closet down at the toilet end, so at least you could put accessible storage? Either way, I think I'd get a sliding shower door, as you don't want a swing so close to everything with glass...

Sorry,

The full length shower on the half of the bathroom would have a bench, and two shower heads, one over the bench, one on the right wall not shown. Since the width is only 30 inches, i was concerned about a 30 x 30 shower instead of a 30x70 shower.

The vanity in place is a very low single vanity across the width, not a double vanity.