I'm against it.
They didn't put in a rol because they wanted you to be able to fire while doing your moves.
Besides, if you're doing a flip, you'll get pwned bigtime. Your screen will just be blurry, you won't see the enemy and when you land you will be disorientated.
As previously stated, there would be no use for the ability and would be pointless for the developers to spend time fine tuning it, while they could be using that time to make sure everything else in the game is well balanced.
I completely agree on this one.