Well, the ATS seems to continue in the CTS's path in terms of being a good offering that isn't based on a lesser brand's car. The XTS is based on the same platform as the Buick Lacrosse, but it's a hell of a lot nicer inside. The exterior isn't that special, but you're not getting that interior in a Chevy or a Buick. For a car that's really just there to fill a space until the real flagship arrives, it's a good effort, especially for GM (much better than I expected from them for a placeholder). And much like the Lexus ES, it's just sort of a car they need to have, because there's a demographic that demands it.
I haven't been in the SRX, so I can't really comment on that. I like the Equinox, but don't really see how it would work as a Cadillac, though it seems to be selling. What Cadillac really needs to do is more to separate the Escalade from its Chevy/GMC siblings. Keeping on the same platform is actually a good thing (beats turning it into a crossover or something). As it stands, the Platinum trim level is the only one worth a damn. Otherwise, just get a GMC Yukon Denali.
If Cadillac can do well with the next Escalade, then all that really remains is the flagship sedan. Those two vehicles are the most important for Cadillac's image. If concepts like the Sixteen and Ciel are anything to go by, Cadillac has the ability to make a good flagship. I mean, big comfortable cars are kind of what they are known for. How hard could it be? They just need to, well, actually release it.
I'm not even really sure where to start with Lincoln. Cadillac at least has GM's bankruptcy as an excuse for why it's taken so long to come out with a flagship. I'm stunned that for as good of a job Ford's done recently with the Ford brand, that they don't seem to have a solid plan for Lincoln.
That's good and bad. Well, good for Cadillac, bad for Chevy. That's the trick with managing three brands. GM seems to sometimes have trouble figuring out positioning, so a lesser brand may suffer for fear of infringing on a higher one. They also have trouble within brands as well, see: Malibu and Impala