It's not so much that buffs need the extra gunners, it's the camaraderie of a bunch of people committed to something together.
While I can run my own squadron bombing missions with formations and have us bomb a target together, it's not quite the same. Squad members will drift out of formation with the rest of the group while gunning or in the bomb sight. Someone being attacked will not have the same dire consequence for everyone in the squadron.
So, I agree that I'd like to see a larger number of positions filled with live gunners. I also like the idea I saw earlier of tying the positions together for each plane in the formation so that you can only occupy for the positions defined for the type, not positions x planes in the formation. In other words, one person could occupy the tail gunner position of any plane in the formation, but you could not have 2 or 3 different people in the tail gunner positions at the same time. However, I would not want to give up the current gunning capabilities for this.