I dont mind yellow, Id just rather a more subdued yellow. Lets not forget, Cadillac alleady has used bold colors, both purple and orange.
I really dont like the rear of the coupe, either. I havent seen it in person, so my opinion isn't worth much, but I still havent seen a single picture that makes the back side look ok.
Thats not enough to discourage a purchase, tho, not even close. This car could come in pink and teal, only, and have flowers and plaid adorning the interior, and Id still buy one...