Some of these points are absolutely fair.

This one though:

Tryhards. We're not super-coordinated, we know it. But when we 5-stack we almost always run into super-coordinated death machines and that's not fun.

After a few matches you should be getting matched with people around your skill level.

I'd also like to comment on:

Of note, getting too used to the AI can also cause bad habits (going for camps at suboptimal times, ignoring objective timing, etc.) depending on difficulty of AI. So that makes it harder to switch to human opponents. Of course, the AI seems to be getting a major buff job right now so the "bad bot habits" may become less of a problem over time.

Playing vs AI will absolutely make you worse, not better. Unless you're just familiarizing yourself with a new hero's abilities.

They can update all the AI's but the AI will never work together like even a solo queue ranked team without any comms would. The AI won't create opportunities. It won't push certain objectives/lanes at the cost of others. It will never (or at least not for a loooong time) recognize meta plays like "hey, I don't see Sonya in her lane, so she must be doing the bruiser camp. Time to either gank her or push the wall." Or "hey, Zeratul isn't visible anymore. Better not push too far from our towers until he pops up on the minimap again."

You won't learn when is a good time to do X or a bad time to do Y because even if Blizzard had an AI that coordinate like in ways actual humans would, they wouldn't release it, because it would drastically increase server costs due to the increased computing power required.

I get that it can be fun to hang out with friends and just shoot the shit but doesn't it get boring to know you're always going to win without even trying? Even Bronze players don't lose to elite AI unless three of your teammates have strokes and/or just go AFK for no reason.

And even if PvE is your thing because humans are scary - aren't there much, much, MUCH better games for that than HotS?