Ive been bugged by these points you get on zbrushs primitives. The model I made yesterday always had a problem with its nose because of it, so today I thought Id start with a square but Ive found the same problem staright away. Does anyone know how to get rid of these irritating points? I thought there were two types of sphere primitive, one that was a genuine sphere, and one that was kind of a squarey/sphere:p type thing. So annoying. Hopefully this pic illustrates the problem. I try modelling over these regions, but any smooting just capitulates the whole area.
The parametric ztools are designed so that you can change their shapes before converting to a polymesh for sculpting but they will always have these poles because of their formula-based nature. If you simply want to sculpt a sphere then the best option is to load the PolySphere from the ZTools folder which is a subdivided cube. (This is loaded by default at startup in 3.5.)
HTH,