Here's something to think about: I think that Jeff not being into prog metal is about the MOST prog metal thing about Sons of Apollo. I've long said here that as much as I love Mike Portnoy and his music (well, his music) I think he suffers when he tries to do too much, and compartmentalize. I don't think it's productive from a creative standpoint to have a "prog" project, a "thrash" project, a "pop" project, a "hard rock" project... I think the best music comes from the intersection of ideas. Dream Theater didn't start out as "prog metal", they started out as a bunch of guys that liked Metallica, Rush, Maiden, Journey and Queen, and their music reflected that.
I think Jeff bringing in the stuff he likes - non-prog metal - is good for the project, certainly better than him spewing out prog metal clichés and tropes.