Dunno if i'm ready to call it OP, but it's certainly a huge difference in the matchup.
I've been playing around with the phoenix harass that I practiced with Indie, but as soon as it's scouted, spore crawlers protect the mineral lines and just a few hydras do the rest.
If the zergie doesnt throw down spore crawlers and tries to get hydras/defend with only queens, then phoenixes can put some serious hurt on the zerg economy.
There is
always that timing window if it's not scouted for protoss to do some damage, but it doesnt last long and once it's over toss
must capitalise on the advantage before zerg begins to outmacro them again.
If I'm playing off of one base, it's not easy at all to get a large enough harassment force of phoenix/VR to worry a zerg into hydralisks and
then switch up into colossi (which requires going down a whole new tech path) in a safe way. Two bases' worth of air->colossi and a zerg will already have expanded ad infinitum, so they'll have more than enough economy to tailor their army on the fly.
So a zerg can very easily temper hydra production to adequately counter a reasonably air army, then transitioning into roach/corruptor to take on a ground assault is far easier (plus it shouldnt take up all of the larva unless the protoss is all in with air, so zerg can continue to expand).
I dont think stalkers need a range buff however. In fact, I would argue that stalkers should be made
cheaper, say, to match the cost of a marauder (nothing more horrifying than 2 marauders kiting your expensive zealot and stalker).
As Kar says, protoss unit cost efficiency vs Terran is terrible before higher tech. Now that roaches are so strong, the same is becoming true vs zerg. The exception is zerglings, which get rofl-imbastomped by zealot/sentry. But roaches are so easy to get out and so strong now that there's very little protoss can do in the early game.
Once Templar/Colossi are out, we can throw down 500 dps without too much trouble, but before then we just need a bit more unit efficiency. All other units are well costed imo, but the stalker is so expensive.
On the other hand, in large numbers, blinked stalkers can be very powerful, so it's a difficult one to call. Although, hydra/ling or roaches with a decent surround should take down a stalker ball without too much difficulty.
Bit of a braindump in this post. I dont want to call imba, as it's not been that long since the patch and with such a shift in the matchup there's still time for protoss player to explore all options. But it's certainly at least balanced the matchup. I personally thought the balance change was borne out of the large process of balancing ZvT, against hellion harass and reapers. It's certainly had a dramatic effect on both.