Your color scheme is pathetically boring. It's not organic, it looks forced. It's not advanced, it's basic.
Your website is crap in terms of organization. Your Platinum series tab doesn't even list the XTS.
The CONTENT part of your website is like half the size of my screen. There's so much empty real estate flanking the sides that remind me of how similarly barren your lineup has been.
Frankly, none of your current cars are as exciting as the Ciel. And yet you hide it in God knows where. Meanwhile, Mercedes is putting its ugly concept on its front page on a timed slideshow touting its historic innovations. Where's the story about Cadillac's history and innovations? You forsake your history for what reason? Cadillac and Mercedes are indisputably two THE of most important brands when it comes to the modern automobile, especially Cadillac. People like historic luxury. Your cars are part of a legacy from the early turn of the last century, not from 2000.
Again, as I said before, it's not advanced, it's basic. It looks and feels like it's in flash still. There's this cool new thing called HTML5. Even so, the website is BASIC. The pictures are tiny. They're bad quality. Half of them are AWFUL CGI that take away from your product. Get real pictures. Do some overlays of things. Do something. ANYTHING.
GET A REAL CONFIGURATOR. Find out who did Porsche's, contract them, and do it for Cadillac. I don't care if it's identical. Just get a real configurator. I CANNOT ENUMERATE the issues with your configurator. If nobody's noticed it by now, well Jesus Christ, then. Even just BMW's is excellent. ANYTHING BUT YOURS. Your car isn't the focus, it's off to the side. FOCUS on the car like MB and BMW's. Have a DYNAMIC picture in which EVERY CHANGE is visible. Looking at the exterior, you should be able to see the interior change, as well. See: Porsche, BMW.
While we're at it, perhaps you've heard of Mercedes Benz's designo line.
It offers many design choices, usually far above GM's same 3 interiors and 8 colors. You want to be the new standard of the world... Yet offer no customization options? No rich colors?
Unless I'm mistaken, do you even offer a pure white? A green? A REAL blue, not a Chevrolet blue (a bit of a soft spot, as I love blues)? Okay, it's coming for the XTS, sure. How about a DEEP red? For Christ's sake, you seem to offer 3 different colors on silver on the ATS, then that awful light brown on the other cars, that awful gold color... You don't even let people choose their own trims.