Ideally a vocal microphone should do two things;
1) Minimize any "issues"-like sibilance, dullness, harshness, etc.
2) Accent the strong points about the voice. So you may WANT a
mike that logically seems to "overdo" it!
Bing Crosby, for example, thought the RCA ribbons were crucial
in enhancing his classic croon. He could sing effectively lower than most
wannabe basses (including me!) even though he thought of himself
primarily as a baritone.
Also, basses tend to fall within two types-the penetrating "brassy"
kind, and the "mellow" ones.
If you have a really good room, you can generally get the best sound
out of a (true) bass singer by miking them about a foot away to catch the
natural chest resonance rathe than relying upon the somewhat
artificial means of the proximity effect.
With all due respect Middleman, I agree with the production style that
puts the vocals first, and create arrangements that are subordinate
in order to support that, in contrast to more "modern" styles of pop
production. So leave that bass voice in the mix alone!
Chris