No it wouldn't change my mind at all.
I think that last year, from the Australian Open to Miami, he was not perfectly fit, but for the rest of the year there was no such thing like that ... according to himself actually.
It was only a little bit older Federer, like in 2007 after the Australian Open, and against great opponents.
The same in 2009.
Not sure what your saying here but i assume your saying its not a slump but a decline. So what would it take for you to think it was slump? Should he win the grand slam itself? Making it 5 slams in a row? Would you be satisfied then? Just curious.