Federer's changing to a bigger racquet had very little to do with miss-hitting. put a 90 sq.i racquet over a 97 sq.i. and a ball next to the 90 sq.i frame, you'll see that a miss-hit on a 90 is still a miss-hit on a 98, or a 100. Besides, he still miss-hits a lot with the bigger racquet
It had to do with the extra power he needed, and gets from a stiffer (believing it's close to the retail version) and longer main central strings head racquet, that allows him get more depth and power from his backhand wing, thus holding better on baseline exchanges. That came with a price: his forehand lost that laser-sharp precision, and the slice lost venom. His second serve seemed to benefit from the extra power too.
Murray lost a step with age and the hip replacement. He probably wants to follow the shorter points route, Nadal did it, so did Roger. He has the weapons to do it, and he knows way more about tennis than any of us. lets see...