Tidus was brought out of the dream, mainly as a result of coming into contact with Sin. Sin can apparently cross between the real world and the dream world; Jecht and Tidus became real in exactly the same way that Aeons become real when they're summoned. A 'dream', or vision, interacts with Pyreflies and becomes a corporeal, living force as a result of magical processes.
The Fayth certainly were tired; dead for a thousand years, but with their souls trapped in statues rather than being allowed to dissipate a go to the Farplane. Forever slaving away, running the Dream World, and also being used to by summoners to call Aeons. They wanted it all to end, for good. No more Yu Yevon = no more Fayth, basically.
The moral? I mean, Yu's intentions weren't 'bad' persay... fuled by anger, perhaps... misguided even. Seems that the teachings were corrupted though, and of course, the truth hidden...
Oh, he had bad intentions alright. He wanted to bring havoc and terror to Spira, to punish the world for its destructive ways; the teachings were there to show how things 'should' be done. The teachings were corrupted, a little - people believed that Sin would one day be gone, once everyone had atoned for their sins; also, they believed that Yevon had given them the teachings to lead them on the path to redemption, and away from Sin.