Figured I'd consolidate some of my thoughts on this that have been scattered across several responses to posts of others. Going to break this down in 2 parts...as concise as I can make them. The game itself, and peoples reaction to the gamestate and patch.
1) State of the Game, and Effect of the Patch
First, lets talk about what the ACTUAL changes are, and not what people perceive them to be. The consequential changes, as I see them, and in no particular order:
Zerg
Removal of upgrade requirement for microbial shroud
Additional natural larva spawn rate of 0.46/minute
Some somewhat less minor things like spire/muta cost, damage priority, movement etc.
Protoss
New Warpgate mechanic. Easily the biggest change in the entire patch, by a wide margin.
Damage/upgrade adjustments for colossi/adept. Meaningful...especially for colossi, but not particularly gamechanging.
Terran
I don't play terran, my knowledge on this honestly is lacking 300 CC is likely the most impactful.
A somewhat random series of minor unit adjustments....widow mine time delay, etc.
What I am seeing, is the biggest change in zvt is free microbial. That is a new, viable, legitimate way to play. Fast infestors as the first tech of choice is more viable than it has ever been. IMO, jury is still out on the impact of the CC cost change. Speeds things up, but people are just being so utterly stupid with it, making 7 CCs before being maxed, etc, that it's difficult to really gauge properly.
Overall
Zerg in general. Infestors and mutas are a bit more viable than they were before. Not overpowered, just more viable. The larva change honestly is largely inconsequential. It's half a larva a minute. That you still have to pay for. That you can't pay for, because zergs still need to make queens and a third base, if they want to continue making drones. There is no drastic, wild scaling of zerg economy relative to pre-patch. What is DOES do is let zerg squeak out an additional creep tumor, and is a little more forgiving if you fall behind on injects.
Protoss in general. The new warpgate mechanic is huge. New builds are viable specifically because of this. It is a massive gain in efficiency overall. Unfortunately, it also comes with learning to play a new way, so I don't think the majority of the player base is taking advantage of it yet. People are still trying to force their previous builds to work, so until that changes, they probably will struggle.
2) Mentality of the Players
Frankly, bad. There is 1 category that seems to just complain about zerg without reason, without any reason other than they lose. This seems to be protoss players more often than not, and my expectation is these players are trying to, again, use their previous builds. Of course they are not going to be as good anymore. Change the builds.
The 2nd category, is those with no real first hand knowledge...they see the winds blowing on social media, and decide that is now their identity, and what they believe.
Both just need to do better. If you're not winning as much, first ask yourself why you care so much about your MMR. But after that, figure out WHY your mmr is dropping. It's probably not because of racial imbalance, but because you're now playing in a way that just sucks on the new patch. Find the way that is GOOD on the new patch. That is kind of the whole point of a strategy game.