What it all boils down to, is that combat in PF2e basically is built upon the illusion of choice. Yes there are plenty of choice, but it is an illusion since all builds always end up doing the same thing every turn in combat because it is the optimal thing to do. So combat i PF2e is in spite of all the choices just as "samey" as it is in 5e. And if he has to choose between almost the same combat experience where one of the systems is very complex, and the other is not, he knows what to choose. And it aint PF2.
Okay, first off should preface this with the fact that I'm not huge on Cody to begin with: I've come across his stuff before and his affect just kind of grates me in a way that's hard to describe. Apparently he's in marketing, and maybe that's the reason my Midwestern-brain is picking up subconsciously, but for whatever reason he just kind of doesn't do it for me, even in the 5E stuff he's done (and he's done some alright stuff; his "Deadliest Stuff at __ CR" list was pretty alright). I kind have to skip around because he likes to repeat over and over things without really adding much substance (Maybe that's why his list came off better: the structure forced him to keep things moving).
What he talks about is "illusion of choice", saying that the players have a great many options but no real choices because there is an "optimal path". I think he discusses how his druid always turns into a T-Rex for all the combat encounters as an example of someone who has a great many options, but feels there is only one choice. He discusses the idea that the feats you take create an optimal path by which doing other things is "suboptimal".
And to be honest, this whole thing comes off more as a player/GM stylistic thing than anything. Like, if you are building encounters where everyone does the same thing, then the obvious solution is to start redesigning your encounters to force them to do other things, as well as trying to push your players out of your comfort zone. If you have a druid who changes into the same thing every time, then switch things up so they don't: use flying enemies that a T-Rex can't reach, use a smaller area that a T-Rex can't fit, etc.
At the same time, maybe it's the players, too. Sometimes people fall into paths and ruts, and convince themselves that they only have one option. Players get lazy, disinterested, whatever. That's a point where I talk to a player, see what their problem is, and see what I can do to help. Maybe the player thought that turning into a T-Rex would be cool every time, but aren't tuned in to how to make that build actually work beyond just turning into one thing. Really, both these problem seem less "system-focused" and more "group-focused", but not knowing the people it's hard to actually diagnose because he's relying on evidence that is purely anecdotal rather than, say, really showing mechanically that there is an optimal path. That's not to say that there couldn't be an optimal path there, but it's hard to take the evidence he gives as a system problem rather than a personal one.
Though his brief hit on diplomatic crunch at the end really makes me just roll my eyes.
Personally, I think this is a fairly well-reasoned and not obnoxious response (because man, some people are reacting stupidly to this whole thing).
One point everyone has missed so far is that he says that the problem doesn't really get bad until around 10th level. So not that big of a deal if your normal games don't get much higher than that. (Disclaimer: I've never played Pathfinder, 1E or 2E.)