In the months after finishing it, I realised that I should have used a smaller bath, which would have fitted against the far (shorter) wall.
I've lived in houses with small baths, and they're crap. Either fit a proper sized one or just a shower.
Personally I'd go with a shower, and not worry about bathing any potential future kids. When they're small you can just use a baby bath, and as soon as they can stand just shower with them.