You really just need someone who rebounds well and provides some kind of defensive skill the meshes with the other frontcourt guys. Greg Monroe's strength isn't weak-side defense. The Pistons need someone on the roster that who can cover block/alter shots at the rim. They also need the right perimeter guys to put our bigs in the best situations. Right now that's only Zombie Tayshaun. Greg Monroe can peak at around 15-18ppg, which is fine for your top big man scoring option. But he's going to be most effective with complementary players around him. There aren't many of those on this roster.