My perspective comes from a solo synthesist arrangement in which there are no other musicians and no other sounds, but only those produced by the solo synthesist. When you remove all other instruments and instrumentalists, it's amazing how much musical room you have for yourself. Elements such as a singer's voice, a drummer's cymbals, or a guitarist's power chords occupy an immense amount of sonic room. In such an environment, it is indeed prudent for a synthesist to limit his or her number of voices. But in the soloist environment, where you've got to occupy all the sonic space yourself, and where little imperfections such as note re-assignment "pops" are painfully noticeable, the wisest policy is, the-more-the-better. The greater the number of voices available, the better. The bigger the sound potential, the better. The longer the keyboards and pedalboards, the better. That's one of the reasons I'm all in for the Prophet REV2 sixteen-voice, even though I'll approach it with a certain amount of caution, just to make certain it really does sound as good as, or even better than, the Prophet '08.
In addition, my style of music does not use sounds and effects such as distortion and feedback that often leave little room for other sounds and effects. With the exception of massive organ, brass, string, and other large scale pads, the sounds used are very clean and light. For example, one of my favorite accompaniment sounds is called "PWM Piano," which I use quite often. With this patch, I could easily play arpeggios that cover the entire range of a five-octave keyboard without creating any muddiness or lack of clarity. For such a part, six or eight voices simply do not suffice. There are other sounds, such as dreamy pads with slow attacks, long delays, and slow filter sweeps, that demand ten or more voices if they are to achieve the beautiful mysteriousness that I'm after.
I could go on and on here, giving many other examples, such as bell and carillon patches. My simple point is, for solo synthesizer music of the more classical type, the more voices and sonic power the better.