I'm with you guys on the extra octave.
4 octaves for Mono/Para synths is ideal.
5+ octaves for poly synths with 5+ voices.
I don't really get the point of skimping an octave from the above listed minimums... If space saving is really a concern, just make a desktop/rack unit for that demographic, and build these premium synths with player's keyboards.
An octave range for bass notes, with melody spaced 1-2 octaves above... that's pretty standard playing scheme. I've found that with the Pro3, I end up playing a lot more with D or E key signatures, just because the keyboard constraints... that's actually the thing I miss the most from selling my MatrixBrute... the extra octave.