1. Not really.
He is both wrong about "every" numeric increase giving you "something" in the "old days", as well as mistaking a deliberate feature for a flaw in rolling a linear probability against a bell curve generated base, particularly when said bell curve generated base has been replaced by a variable point buy base.
However, other than having to be careful in rewriting the rules, there is nothing inherently absurd about replacing the ability scores with the modifiers and just going from there. Instead of rolling against an ability score, which I'm not sure even happens anymore, you would roll against a static DC 10 with the modifier, and the whole thing would be a near statistical wash.
As it happens, I noted something quite similar myself in respect to supplanting damage ranges with "average" damage results as "4th" edition progressed.
2. In this case you are way too kind. This is JUST the anti-Vancian rant yet again. Never mind no original solution, he doesn't even have an original complaint.
3. For this the problem goes deeper.
He whines specifically about "high fantasy", casually handwaving past any consideration of whether people want their D&D to actually be high fantasy, and gratuitously bypassing the relatively low-fantasy Thomas Convenant books which very prominently featured mundane martial artists. (It is difficult to quantify that series as high or low fantasy. It normally proceeds as low, but the background and villain are high and beyond.) But guess what? When those mundane martial artists come up against the high end mystical threats they suddenly wind up with crises of effectiveness when they realize they can't punch colons up through throats, and so can't really hang and bang with the big boys.
4. The Save or Die argument combined with the Active or Passive Defense argument combined with the Who Should Roll argument.
But he cannot be bothered to even address them all in a functional manner.
5. Not really.
He conflates protection against being burned by brushing up against something hot with actual protective clothing worn by firefighters with the impact and piercing protection of armor, completely forgetting that people, you know, die from heat stroke while wearing armor, but it should absolutely protect you from being burned even as your breastplate turns into a pressure cooker.
He struggles to make a Realist vs Simulationist argument, but falls far short.
Oh, and "increased complexity".
6. He wants to ignore how attitudes about the game have changed without seeming to be aware of them. Not particularly impressive.
7. No, he is complaining more the number of caster classes, not how many people want to be casters. He wants to reduce all spell slingers to wizards and druids, and everyone else gets to run around being mundane. Apparently customization can only be for spear fodder.
8. More than that. See above where he wanted to reduce the number of caster classes? Yeah. He doesn't seem to realize that by cutting out such variants he is actually contributing to the stereotyping that he despises because he wants such limited potential.
Likewise he also wants to handwave any sense of distinction between races. After all, if an orc can be as awesome a wizard as an elf, what exactly is the difference between being an orc and an elf? Fangs versus pointy ears?
That right there is the handwaving of fluff that made "4th" edition so absurd, effectively confessing that the designers had no ability to write distinctive fluff.
9. "Wah! I hate alignment! I hate fantasy archetypes! I don't care about genre!"
Wait, was I supposed to read anything else there, particularly after his previous complaints about power gaming and too many caster classes?
10. And here we get into the difference between literature and games.
As a matter of fact, I remember a book where the party went off on their quest with 2 greater artifacts, 1 lesser artifact, and 1 suit of armor worth more than a country. Along the way they picked up a few more lesser artifacts and a dozen or so magic items. They didn't buy those items, but most were custom selected for them, including the lesser artifact.
That book is of course The Lord of the Rings.
But never mind what people thought of them wandering around with such fabulous treasures, let's focus on how many peasants they could have fed with them. Even though, you know, one of the lesser artifacts was actually super-fertile magic earth that helped rebuild a country that had been devastated, enabling people to eat.
Overall, you are way too kind.