I can write the "GM put a truck engine in the Camaro" thread right now. That shouldn't happen. If it does it shows GM is incapable of making a decent world class product.
GM also tried a 3.0 L V6. It failed misserably because of the lack of torque and HP compared to the 3.6L. If you recall, GM launched the Equinox and SRX with 3.0L V6s and made that the base engine in the CTS. It had exactly the numbers everyone was looking for. It was not an EPIC FAIL, but it was a pretty big one. Took two years to resolve it. It gave you less power and performance and no real FE gain for the trade off.
Now if this is one of those threads (like the mythical 3,300 pound Camaro that everyone thinks is coming) that says GM should make a XXL V6 that gets 35 MPG and offers more HP than the current 3.6 and gives us V6 buyers the performance of an SS for no extra money..........................well we should shut that down right now.
Yes, GM could make a 3.0L V6 and put in the Camaro. Name your displacement. But you will run into one big problem. If you want a bigger displacement for more torque and HP you will LOSE FE, not gain. And if you want a 35 MPG Camaro, you will LOSE HP and Torque, not gain.
There is no free lunch here, guys. You can't just say "invent an all new V6 that gets the HP of an SS and the FE of a Chevy Cruze". If that could be done it would have been done.
And then there is the crowd that says, "I've got a tune and I make 350 HP in my V6". Nice, but your engine and the transmission that goes with it no longer meets GM standards for reliabilty. Sorry.
Basic point - it's just not that simple.