Yep you are pretty close with the condom! actually I had mine fitted by the scubaland shop, it cost something like €30 delivered back to me.
Believe me If you spend enough time in the water you will come to appreciate the convenience of being able to "let yourself go" with a Minimum of effort.
Besides urine actually attacks the glue and rubber in a wetsuit.
As Miles says the extra 5mm or so of rubber over the chest and shoulders makes a bit of difference.
The Picasso glue is amazing stuff, my buddy got a new Spetton with the gold thermic inner and wouldn't listen that it is a little more fragile than open cell, tore a big hole in it! a little rubber glue and he was back to as near as new.
Regarding Arse wear , I always get in and out facing the sea, I don't like the idea of being caught by a rogue wave so thats where my arse gets worn
