I have never understood why at times the issue of manpower in realism matches is an issue at all.
In all honesty, why couldn't the excess german players switch and play Russian/Allied to make up the shortfall. IE-for a TOC match, we have 4 german units and only 1-2 allied units. We always have an excess of german units wanting to participate, and not as many allied, although of late they have done well number wise.
I personally would have no problem playing allied in a match I could not participate in, and only an idiot would sabotage the effort of the opposing side just because it is not normally the side they play.
I believe the realism community should just come together, hash out a set of rules, if they aren't totally what you want, deal with it and play. (whether that be too realistic, or not enough). And if you occasionally need to suit up for the opposing side, so be it. Then people would never run of motivated enemies to fight.
I'll happily storm across the russian steppes towards moscow, or fight for the motherland and take not one more step backwards. To me, it's all in the fun of playing.