wizard/warlock used to be a popular build, still is if you can farm one
forgot link but there are a few guides for them somewhere on here.
not to suggest anything but warlock chars are hard to bot so probably reason you dont see them often. anyways warlock/wizard or warlock/cleric pvps equal debuff, trap, sleep then meteor or offering and other person is dead

even against holyword users, warlocks still do pretty well if they learn to not rely on debuffs and use other combos