We are also in the process of figuring out a redesign for our master bath so your plans appeared somewhat similar to ours. I would suggest though that if you have the space, rather than a 12" wall cabinet, make your vanity 72" and incorporate the cabinet space into the vanity area. 12" isn't very much room to even put a towel so I don't think it would give you a lot of storage. You could put a knee wall on the side of the vanity and put your toilet on the same wall. Move the shower to the other wall in order to make it larger. Without a tub, I think you have plenty of room for a larger shower.