what is next for staminal? can he keep this up?
It's hard to say. After winning his first major he too will become the hunted. Getting his scalp will be a priority for others on the tour, and at age 28 or 29, he will have to endure his sophomore slump. His mental hasn't been that good in the past, even though he's always had the game. So, personally, I don't see him continuing to climb, but I also don't see him descending too much. Much depends on whether or not his improved mental capacity is here for the long haul.
also is he as good or better than Federer now? I know there is a ranking disparity. roger is ranked lower than stan.
No, he is not in Federer's league. He does not have the experience that Federer possesses. He has not dealt with as much adversity and the pressure. He had the luxury of being the underdog. The luxury has now disappeared. Even in the final when Nadal was clearly injured, he suffered from inexplicable blips allowing a player who could barely move manage to take a set off of him. With the state of Rafa's game, that should have been a straight setter. He has a long way to go to be on Roger's level.
what if the two had played the final at the Australian Open? who---in your estimation--- would have most likely won that battle?
Roger. Stan defers to him at almost every turn. He wouldn't beat his buddy if Roger was in a wheelchair.
can stan make waves at the U.S. Open?
Waves, perhaps, but I don't see him winning it. I give him a quarter or a semi at best. By that time he will no longer be seen as an underdog. Blood will be in the water.