The problem, as I see it, is that the rogue gives up a huge amount of survivability for a moderate amount of damage. And uses the talent slots for the damage increases. So while a fighter/barbarian/monk will have his own talents that are comparable with the rogue, he'll also get the survival benefits 'for free'.
Also the stealth mechanics seem terrible for purposes of getting those sneak attacks. Since the whole party is visible as soon as combat starts, you basically either don't get to sneak attack, or you have to send the rogue in alone to get mobbed. Meh!
I think if that invisibility talent was 2/encounter instead of 2/rest, you'd start to have some viability in terms of cost/benefit.