I get the fantasy of wanting to play the bad guy, that’s not what the Forsaken were marketed as pre-Cata nor post-Cata (prior to BfA) though. Blizzard even stated the intent on creating Forsaken themselves.
Bo Bell: But then, there was the epiphany that some people were into playing evil races/factions. Whereas a LOT more people wanted to play as these "evil races (Forsaken not included) but as the good guys (Thrall’s Orcs during WCIII).
So, Metzen needed to come up with something for the undead. We seriously considered dropping them, but every time we looked at concepts/in game assets we balked. Then he announced the Forsaken.