The BMW's scrape the barrel of what I'd call a livery in my opinion. It's just a white car with the flags stretched down the side of the bonnet - all the design work's done before they got there.
I think the Chevrolet is the best example of the most coherent livery in the WTCC (N-Technology Honda pending).
I don't doubt SEAT could probably pull together a livery if they had to, the thing is they don't because unlike most teams in the WTCC, they actually seem to have a lot of sponsors! They're a bit stuck with their sponsors brands, and pretty much all of them clash horribly! White, Yellow, Orange, Red, Blue, Green - considering the colours they've got to work with, I can't really say they've got an easy job on their hands - and have probably come out of it the best they can.
awrb, if you keep insulting the Léon, you're just going to get on my bad side