Is the game meant to be designed around creating a single version of a particular class (D3) or will there be permanent allocations which would incentive players to play the same class multiple times in order to try different builds for that class? (PoE, D2)?
There will be a cost associated with reallocating your characters skills and passives so if players like the character they have and would like to try another build it's likely that they will re-roll another character of the same class. They of course can spend less effort altering their current character but it won't be as easy to switch skills/passives as, say, Diablo III, but less punishing than PoE.