I'd love to be a product manager for Cadillac. IF they have the engineering resources, then they should definitely launch an assault with a wide range of vehicles off the stellar Sigma platform instead of the upcoming Zeta platform. Keep the Sigma platform exclusive to Cadillacs and use the Zeta platform for the mainstream brands (Holden, Chevy, Pontiac, & Buick).
Instead of calling the CTS-based coupe, the CTC, they should call it the CSC for C-series Sport Coupe and CSW for C-series Sport Wagon. Do the same thing with the BLS-based coupe and call it the BSC for B-series Sport Coupe? How's that sound? Personally, I don't think a B-series range fits in with Cadillac's image.
1) They should keep the CTS in the entry-level luxury segment and offer both CSW, CSC coupe, & CSC convertible, along with a $40,000-50,000 long-wheel-base CTS-L sedan available with both 3.6L and 6.0L Corvette engines. Executives would love the CTS-L sedan with a 405hp 6.0L V-8!!
2) Then create a redesigned, bigger, longer STS and its long-wheel-base STS-L version to battle the 750i and 750iL. Beside the new 302 hp 3.6L engine, offer a range of more powerful V-8 engines. A much bigger, longer STS and even longer STS-L would attract more buyers. Look at the Audi A8 when a long-wheel-base A8-L model was added!! Sales shot up!!! The same can be said for the new Lexus LS-460-L. Then Cadillac could one-up the competition by offering an even longer version of the STS-L called the SLS with an extra 6 inches of wheelbase added. That would create a huge rear compartment for ottomans and reclining seats ala the Maybach 62.
3) Create a 5-series competitor called the FTS (F-series Touring Sedan) or LTS (L-series Touring Sedan) or MTS (M-series Touring Sedan). Then add a long-wheel-base (LWB) version along with a sleek sportwagon, LWB estate wagon, and coupe/convertible variants to battle the 5-series and 6-series range.
4) The SRX should not be dropped at all. It needs to be redesigned to look more massive, masculine, and more SUV-like. Right now, it's not tall enough. Look at how popular the BMW X-5 is, especially in V-8 form!!