Honestly I can't give much value to streaming to an ARPG over the long haul. It's just not a game for watching once all the acts have been seen and I don't care if it's D3, TL2 or PoE there isn't much point watching it anymore it's not like it's an e-sport type of game. With that being said playability wise for the gamer and not the "stream watcher" is what needs to be gauged. If a program like Raptr or something was used by a large pool of players that tracks game time played that would show what game players will/have invested more time into.
Sadly Raptr isn't an accurate gauge but I did get my report for 2012 and it told me I played 200+ hours of D3 in 2012 I haven't played in 2013 and my Raptr playtime for PoE is at 127 hours atm and I can only play casually due to RL and other game interests but I can already see I will blow my 200 hours out the water with PoE.