The question is whether it'll be a full-size or compact drop-top.
Convertibles and Cadillacs just go together. It's a fact. But at the moment, Cadillac is lacking a convertible in its lineup. That's a problem management is looking to solve in the fairly near future. As we all know, Cadillac has a history of making big convertibles, so wouldn't it make sense to carry on that legacy (minus the big tailfins)? It really all depends on what the market wants. There are a couple of possibilities for Cadillac here. The first would be to simply cut the roof off the ATS Coupe and call it a day.
This would act as a prime competitor to the BMW 4 Series Convertible and help Cadillac establish itself even further in Europe. The second possibility is something a bit more grand. Cadillac could opt to build a more direct successor to the now discontinued XLR, which was loosely based on the C6 Corvette. In the era of "New GM," it doesn't seem very likely the C7 will be called up for Caddie duties, but there's always a production version of the Ciel Concept. With its suicide doors and bold styling, any production version would surely be toned down. However, the RWD platform that underpins the CTS is a possibility here. Again, any final decision will depend on what Cadillac deems to be most profitable.