not sure about the low end response but as far as a high frequency boost for vocals that could actually be useful for taping as higher frequencies dissipate at a greater rate than low frequencies. Doug Oade incorporated a switchable high frequency boost into the the m248 for just this reason. The Schoeps V caps and mk5 also incorporate a high frequency boost. I can't speak for these mics specifically but I don't think you should write them off just because of a high frequency boost.
Ok, bit of a thread hijack here: I always hear about this issue of high frequency dissipation and how it relates to taping, and I'm just not sure I get it. The way it is discussed seems more useful in regards to taping unampified instruments at a distance, not taping PA stacks. Afterall, the soundman does not mix the sound for how it comes out of the PA stack (meaning how it sound 1 meter off the stacks). The sound guy will presumably mix it to sound right where he's listening at the FOH console. So if you are taping at the soundboard or in the taper section right behind it, the high end should be just about right. I would only think you'd need that high frequency boost if you were taping significantly behind the soundboard.
But nobody talks about FOB in relation to this high frequency dissipation. If the sound guy is mixing so it sounds good at FOH, with the greater high frequency decay, that means the sound coming off the PA stacks is really too bright for what you want, and consequently that there will be too much high frequency emphasis FOB (so that it will have the right balance back by the soundman). So there would already be too much high frequency emphasis FOB, even without mics that emphasize the high end -- it'd get that much worse FOB if you used the schoeps V caps or other mics with a high end emphasis (eg, neumann SD mics).
Does this sound about right, or am I barking up the wrong tree?