I think many people overestimate how much difference 5 square inches would make on reducing Federer's shanks or mishits. Perhaps they mistakenly think that extra 5 square inches in head size translates to extra 5 square inches in the sweet-pot?
How big is the sweet-spot on Federer's 90 square inch racket? Let's just say 25 square inches. Assuming that the sweet-spot size increases proportional to the head size (a big IF), a 95 square inch racket will have less than 1.4 square inches extra sweet-spot.
My personal experience tells me that, in fact, sweet-spot size is not significantly related to the head size at all. What this means is that a 95 square inch racket may not even have any increase in sweet-spot size. It may, but it also may not.
On the other hand, a more significant difference that a 95 square inch racket will have is the feel. That, in my view, would be more detrimental to Federer than any negligible gains that he may derive from increasing head size.
Plus, searching for a new weapon is a time-consuming and risky business. It might be worthwhile for us mortals and even lower-ranked pros, but for a GOAT like Federer it's just not an optimal move. Now that I think about it, this might be an interesting research topic for my dissertation haha.
Wilson Pro Staff 6.0 95.