From all that I've experienced, everything they're saying here is true...a good wash is good enough. Back in the 80's, the accepted standard was "don't paint eyes period", but we've come a long way since then. There are ways to do it and do it well...and if you're really sure you want to try it, you can try to follow in the footsteps of Mark Bannerman
with his tutorials. For me, a hint of dark and light works, but only if you've got a good sculpt to work with. For most figures, even the middle-of-the-road stuff, a dark wash is probably your best advice (unless you've got some incredible small-brush skills!)
I have to agree completely that most figures aren't sculpted well enough to include any real detail...but I recently got to experience Warriors heads firsthand, and I am impressed. I've also heard great things about Hornet.
This was my first real attempt at sitting down with a good magnifier and good light, and I'm pretty pleased. Mostly, though, I'm encouraged that somewhere out there, in very expensive resin, there are heads that can be made fabulous with practice and patience.