I feel like 3E set the precedence on min-maxing, especially since before that (if I recall correctly) you needed sky-high stats to even get a minute bonus to things. 3E had tons of set-in-stone rules about stat allotment if you didn't want to suck. How is a 3E fighter supposed to have enough skill points to be lord of the land, or heck even know how to Jump, Swim, ride a horse, and use a rope, without penalizing themselves in combat?
I will explain myself one more time because I think I haven't been clear enough, probably because I'm not a native English speaker.
I say that 4th edition problems are
NOT original from this edition: they are HISTORICAL D&D problems, only made worse. Of course, 3rd edition initiated a scalade of min-maxing, but this min-maxing was neither the "core" system, nor it was supported by it. Ultimately, the min-maxing
broke the core game (like Pun-Pun build), and leaded to broken exploits. You can go in the core system with sub-optimal combat choices and you still will be useful in a fight (although you won't shine in it, like the bard, a classic diplomatic and support character).
Hopefully one day D&D will either go back to the days where stats relatively don't mechanically matter (or heck, kill that sacred cow altogether), or they do something like in Pillars of Eternity and make all stats (almost) equally useful to all classes!
I agree with the last part. Throw the dump stats and make every stat count. I think that, although not perfect at all, the six saves are an approach to this.
Plus, especially compared to 3E, the gap between "beginner or average player" and "min-maxxing munchkin" is much smaller, making it so much easier for the DM to plan encounters and to keep players from being overshadowed.
As I said earlier, the problems in 4th edition are not exclusively 4th edition problems. 3rd edition has his own account on this, but the "core" experience (killing orcs/dragons/whatever with sword and sorcery) is pretty straightforward, with plain old hack&slash/ fireball spells. You don't need to know every power and see what is more effective. Now and then, the fast thinking can make you confront harder challenges.
And yet, you don't have to fill a specific niche to be useful in a fight. You can always support others that shine in it. A sub-optimal combat character, in 4th edition, is a hindrance to the party because the heavy combat focus. Aid in 5th edition, for example, is an action destined to help the most effective fighter to achieve his goal. And he can help you in your diplomatic efforts in many ways. Maybe as muscle intimidation.
I also feel like you've totally got the wrong opinion in point 4... One of the
key strengths of 4E is being able to make and adjust monsters super easily. Want to increase that orc 10 levels? Bam! +10 to each defense, +10 accuracy, +10 damage, and +60, 80, or 100 HP depending on what role it is! Want to spice it up? Copy and paste a thematically appropriate ability from a similar level monster to it!
And from where they come from? They were summoned from thin air? Why the super-12 level orcs aren't destroying cities and empires, if they have a dragon ball-esque scalade of power, where a ten levels of difference are so huge that no one can touch you? This orcs can fight dragons mano a mano!
This is what i've said about verosimilitude. At least, other editions made "high level foes" defeatable by raw numbers, or Infernal, or draconic. But yet, 3rd edition has the same flaw. Flatter progress made numbers significant in a fight. So armies have a purpose: to deter the high leveled foes of going solo against entire cities. The mind flayers have to rely on politics or amassing power with orcs and goblins. Yes, a single 1/2 CR orc is not a difficult fight for a level 10 fighter. But ten well equiped, coordinated 1/2 cr orcs (they won't have to increase their stats: a simple shield and chainmail increase their CR to 1 or even 2, and heavier numbers can increase them further) can pose a several threat, and unwary decissions can turn the tides of an otherwise easy fight a total disaster.
That is what I say about level balance; you don't have to be from a certain level to fight a certain foe or pose a threat to them. The odds won't be on your side, but you can still manage to be useful. For throwing an example: in a gladiator fight, one of my players had a 4th level half-orc paladin, and fighted a Gladiator, a CR 5, but I gave the gladiator a better armor, so his CR go to 6. And the paladin have four previous fights, one against an ogre with chainmail that almost kill him until he used a spell to frighten him. And the paladin had a splint mail, not plate nor magical weapons. He won. Notice that the foe has two levels more than the whole party, and Nahuel fighted solo and without spells. Cunning, a certain amount of drugs (the character became an addict paranoid afterwards), a bit of luck, and grapple&prone made the trick. Yet, he had the most difficult fight in his life
I don't understand your complaint that being stabbed in 4E won't kill you. They changed the average hits to kill and die so it wasn't such an unforgiving game of rocket tag.
Tucker's Kobolds. Fight smart. There were several ways to lose a fight without die (if you reach 0 hp, you can go through 10 rounds alive). I've played for 5 straight years AD&D and my characters never had to use a Resurrection spell (unexistant in our world), althuogh they lose several battles. Further levels can make you more difficult to kill, but gritty realism is a great option to play. If you don't like it, begin in higher levels (an option present in the core books). But this point was made to prove the absurdity of HP, a valid criticism to D&D, but ultimately a lesser evil to make fights easier and shorter than tracking specific wounds.
I do have to question why you think all 5E classes are balanced, or why you think the classes in 4E are fluff outside of their roles, among other things, but I'm not sure if that would lead to any decent discussion or if our opinions are just too different...
Every class is useful one way or another in any given situation, although all of them shine on certain aspects and have very different approach on how to handle a problem.
As I said earlier, generalistic rules with specific exceptions are a more fluid approach than closed-niched combat roles. Yes, a thief is better at opening chests and finding traps than a cleric or a fighter, but they can make the trick (slower, true, and without such grade of effectiveness). A fighter can tear apart a door or a chest lock with an axe, or try to use a lockpick anyway, with a chance of success. Why classes are not that fluffy-over-roles in 5th edition is a long conversation, that we can discuss in another time. In short terms, a cleric is an excellent spellcaster, but the roleplaying approach of this class is a mechanical factor: you don't follow your god's rules (praying, for example), you have not anymore powers (or at least that is was used to be in AD&D). See the Oathbreaker paladin in the DMG.
About dissociated dynamics and vancian magic: I don't see how don't you see that Vancian system is still used in 4th ed, only that in every class and in a tigher frame. Instead of having magic powers by day, you have martial powers by encounter
and day. Blast me if they aren't micromanaged vancian martiality. How "balance" 3rd edition the vancian system from 2 edition? By giving more daily powers. How do it 4th? by giving a more limited timeframe... and encasing every class in them, even when it have not sense at all (see Martial
daily powers and dare to say to me that they are not "vancian" in the terms 4vengers seem to hate from prior editions). This is not "cooldown", this is plain old vancian magic

.
As I said: the problems remain the same, only explicitly in front plane. And I certainly don't see GMing as a flaw, but a core part of the game. The GM is there to interprete the rules when the players want to think outside the box. Give them back control over their tables is not a bad thing: I'm playing 5th edition since it came out, and I only change one rule: I permit to stack inspiration.
And the rules are there to have fun, not to convert your games into a trial and your players into lawyers. Is interesting how many 4th edition fans seem to hate every rule that is not a combat mechanic but a roleplaying mechanic, as Alignment (that wasn't as straight a jacket as many may think; it is a general guide of behavior and personality; it has sense that a paladin has to follow a certain code rules, because as a fact their powers came from them). And you always have always Dark Paladins (as much as I hated them over the years).