I'm assuming the SAGA system is what the first games used? I doubt that too...though you might see similar names (such as Guardian, Sentinel, Consular) for example.
Actually, as I write this, I could see Guardian, Sentinel, Consular being the equivalent of talent trees if they were to blatantly rip off WoW. Or they could be different classes entirely, with their own talent trees (I do think that the talent trees will be ripped off, as well as much of WoW's mechanics actually...not that I think that's a good or bad thing).