Absolutely AGAINST (...) full character customization, as that will cause imbalanced builds to break the gameplay.
Hehe it's PvP and that's exactly why it's fun. People breaking gameplay, people just playing other people ideas, people complaining, and players who find the way to think about "outside the box" builds.
You just need PvP skill balance and enough choice of skills to let your players find appropriate answers to any strategy.
Letting more freedom/customization require more work from devs for sure, but it's the royal way to build something really really successful.
Look at DotA: built from senario editor in warcraft3, blizzard gave the tool and players imagination built one of the most played PvP concept since a few years.
