Having thought a bit more about this, it is not inconceivable that actually even battles like Phillipine Sea could have been much less of a walk in the park than it was in OTL for the americans. Imo surely the japanese plans must have been for massive, coordinated airstrikes, but everything got unravelled on the 19th of June because of many poorly trained aircrew and probably luck too and they attacked piecemeal in four separate waves, being practically anihilated in the process. But if coordination would have been a bit better, maybe if they flew a bit lower to reduce the time they will be seen on the US radars, perhaps two deckloads of strikes from the carriers, one of about 200, another of about 150 planes could have overwhelmed temporaraily the F6Fs (not all of them were airborne at the same time, the largest number during the OTL battle was apparently 142) and go through to at least one of the TGs. Sure, the flak will be murderous, but they should hit some carriers, maybe some pilots will commit jibaku, and sink one or two of them (the CVLs being more vulnerable). The second wave could again damage a couple CVs, and all in all the americans might lose 1-2 CVs and have 3-4 damaged, and maybe 200-250 planes in all. The japanese will still lose almost all of their carrier planes and pilots, but at least they will have something to show for it. With fewer operational carriers the americans might send fewer planes against Ozawa next day (if any at all), which might prevent Hiyo being sunk. Bonus points if Taiho survives too, it was a lucky hit that caused it's sinking. So the japanese might only lose the Shokaku in this ATL.