I agree with you(but there is no way it's beating WoW)
I'd consider it niche though because the crowd it appeals to the most is the hardcore PvPer(even though I agree it has other aspects that attract other people). No other game coming out or already released has as many PvP/PK/grief centric features as Darkfall. It's an anomaly among current games. Much like hardcore PvPers are the minority in the gaming community.
I agree what you're saying though, It'll still garner support among other types of players. I aint the DF naysayer here.