The only way that I think it's reasonable to put a V8 in it is in the scenario I outlined before where the cost of a Cadillac corporate V8 is spread out over multiple vehicles. Otherwise, and I know I will get flack for this, I don't think a V8 is needed here just for the sake of putting one in. The Lambdas are close in size to the GL, but they're also even closer to the Audi Q7. Audi stopped putting the V8 into the Q7 a couple of years ago and they sell plenty of them just fine. For the kind of driver these mid-tier SUVs have, high feature V6s are MORE than sufficient, especially something like the Twin Turbo V6 that's in development now. Perhaps a slightly de-tuned version. Vehicles like this are where I am willing to make the sacrifice of having a "just because V8" so that vehicles that are ludicrous WITHOUT a V8 can have one.
If anything, this should demonstrate that I'm not blindly riding the V8 train anywhere and everywhere possible. There's places where it's RIDICULOUS to put out a FWD non-V8 car, and others where it will compete just fine. The Enclave is at the top of its market, and so long as the FULL SIZE Escalade remains, a properly executed Cadillac version of the Lambda will be even better.