If blizzard succeed then:
If 12 DPS classes are brought by equally skilled players with equally decent gear then they will all be within 1% of each others DPS.
The only real differential in potential DPS is to be skill.
Your warlock will be fine at DPS - but if I am more skilled My shadow priest will be doing more damage.... and the ret pally who lives in game and knows everything about his spec and playing style will beat us both. Good times - I cannot wait.