We've found a rectangular cubicle rather than a small square one is great, we were used to the space of a wet room but the floor leaked and we had this on the insurance.
A thermostatic control is a good idea if there are others likely to run taps or whatever when you're in and, going back to the cubicle, a sliding door with a magnetic seal to avoid puddles while you're doing the moves to your singing.
Having the drain the the corner seems to make drying the tray easier too AND you can get a non-slip but shiny finish so no need for a rubber mat.
My mother had a fall last year and wrote off a hip so climbing over the bath was going to be problematic, she ended up with more or less the same as us and loves it.