Since I'm not big into mixed doubles, I have to ask:
Would the most "fair" team be a 3.5M/4.5F team? Honest question, it seems like that and 4.0/4.0 would eliminate a lot of the issues you talk about, but I rarely hear people metion the 3.5/4.5 combo.
Sometimes I use big words I don't really understand to make myself seem more photosynthesis. -JR