Kyrgios plays with a Yonex, interestingly enough but not the Wawa. He plays with the Ivanovic stick. Make of that what you will. lol He does have great touch and a willingness to risk shots. He may end up being a better clay court player than hard. It'll be interesting to see.
As for Fed changing his sticks with every new gimmick, I too don't believe he did. But I do think the last 90 was different from say the NCode 90. If you watch the way he swings each stick you can tell the difference in weight, to my eyes at least.
To wield a 90-93 inch frame on the tour today requires a few things that most players today didn't, don't or can't do.
#1 You have to play with it while your game and strokes are still developing. There's no way a Nadal or Kyrgios is going to swing a Tour 90 the way they swing their Babs and that Yonex. It's never going to happen. The 90 will never generate enough power, spin and give enough margin for error, aka "power spot", for those strokes to be effective. This is the MAJOR hurdle to players using mid-size frames these days. I've watched it with so many juniors and pre-juniors. They get so much more power from Babs and similar frames when they are physically too weak to generate it themselves. So in order to simply keep up they use the more powerful, more forgiving frames and never learn how to generate the power themselves. Look at Kyrgios physically. Nadal coming from clay courts is an exception
#2 You have to be a darn good athlete with the ability to hit winners on the move and in transition from both wings, meaning you need a 1HBH. Courier probably would've won at least another French if his strokes had been grooved around a larger, more powerful frame, and Poly strings, Agassi possibly as well.
Right now I don't see any ATP players outside of the top 5 or so with the overall athletic ability, style of play and strokes to use a 90-95. Djoker probably could but being a baseliner with an OK serve and minimal net game, it would offer no advantages to counter the many disadvantages.
