I think the idea of a Cadillac version is cool. But at the same time I don't think it is necessary for a couple of reasons.
The first is Mercedes and their recent statement that they are pulling back from all those sporty high-end vehicles that are killing their margins. I translate that to Mercedes is taking a financial bath on those very cool vehicles as the market isn't as big as they thought.
My memory is the original LFA didn't sell that well, I think 5 years after production ended there were new ones still available for sale. And didn't Audi discontinue their mid-engine car? Even BMW doesn't really play in this field very much - I'm getting at that this might look better on paper than in reality.
While I think the BW's are a great addition to Cadillac, is something like a mid-engine vehicle be where they should focus their resources? For a low volume vehicle, I think their money will be better spent on something like a Sollei. Granted a Sollei will be a lot more $$ and GM can certainly focus on multiple projects, but I think a Sollei will do a lot more for Cadillac and a better fit for the brand.
And then there is the comparison factor - GM literally threw the kitchen sink at the ZR1, I'm thinking there isn't a huge amount GM can do to make a Cadillac version better. And does GM want to make a better version than the Corvette, the companies sacred cow? Whatever Cadillac does, even making it a more comfortable and slightly less performance orientated will still have a ton of comparisons to the presumably cheaper Corvette.