Well, I would agree that the 2005-2008 LaCrosse is not particulary innovative, but the proportions are to my liking. It's well-balanced. I know people mention the overhang and I now see what people are talking about, but viewed in profile, the hood's relationship to the trunk lid seems better proportioned. I also like the rear view with the crease between the lamps and the C-pillar with the roof rails as well as some sense of verticality.
Look at how the timeless proportions have sold cars. The 76-77 Cutlasses, the 81-87 Cutlasses, the 88-96 Grand Prix in coupe form, the 98-02 Intrigues, and others. Even the DTS which harkens back to a more notchback type of sedan picked up in sales over its predecessors...I would have never looked at a Cadillac and then, seeing them around, took note...that's a beautifully proportioned large car. I think the LaCrosse hasn't sold as well because of our crappy economy, the fact the more and more people think American cars are not cool, and, to a point, because the W-platform has been around for a long time.
I think the vernacular of the new LaCrosse is trendy and won't be timeless. The roof that's gone through the flattener, the scrunchy greenhouse and the overly angled rear backlite that flows into nothing of a trunk lid will be a passing phase.