Why Not keep the head size
Well Wilson appears to have molds and is playing with constructions:
eg-materials, flex, balence etc.
A suggestion is take the same headsize but change the mold. Having done Mech Eng @ Uni, i thing this could yeild some good results.
-22mm thick beam on the frame
-No PWSsame string pattern (or maybe try a stream type pattern for Inc spin)
match the same flex pattern, so the frame may have reduce flex (more power), but flexs in the same places etc.
-Keep the 90 headsize
-Possibley reduce the weight
About 20 years ago Head made the Graphite tour 600, this was a lighter more powerful frame based on the shape of the original Prestige600.
My idea would be Wilson doing something similar, as the thicher beam will give more power (compensating to fell swing speed), a stream string pattern will create more spin/ controlling the power., & lighter weight increasing the potential to swing faster (as even a lighter frame can match swing weight).
Recently i got the chance to use the Volkl Organix V1 Pro, now i like the prestige (had a few of them), and the DNX 10 MId, so trying this frame was a huge revalation. Just so much easier to play the same game as i usally do, just felt so much more controlled and more result for the same effort on my strokes. So after this i fully understand what FedEx is trying to achieve.