TPDC - You are being way to hard on yourself! From the pictures there appear to be a few bumps, but over all I think it is simple and beautiful.
With cakes such as this, it's hard to hide the flaws. You are doing the right thing by contacting the bride and letting her know that you (personally) are not satified. It will go a long way.
Personally, I think you will have more problems out of the other two guests that wanted the cake more than she did... At least your not dealing with them!
Although I am new at this and I'm practicing, it took me forever this morning to smooth out two BC
cakes. I don't know how you do this on a regular bases without pulling your hair out! I nearly pulled my hair out on practice cakes!
Hang in there...