After reading PYRO's explanation of how the buff gun system is going to work, I thought it was some ingenous thinking. Damn great idea IMO.
As he said there are a few down sides, but no matter what you do there will always be downsides. The main thing, that has already been psoted here is about multiple bogey's. PErsonally I don't think this is a big problem if you consider the likelyhood of 1 50cal bringing down an a/c, it seems to me that to get the job done you would need a concentration of fire from different guns regardless.
The implemetation should be pretty good to, gunners will place themselves strategically in a gun position with the most lines of sight to basically "direct" the rest of the gun crew. The top turret for example will be a great position, having a huge field of view, you will be able to switch targets quite quickly and easily. With practice we'll have alot of deadly gunners out there and perhaps a new column on the scoring section