I agree with most of your previous points, but this one I'm not so convinced of. There are degrees of consistency, and 4e is definitely noticeably less concerning with any kind of in-game reality than 3e ever was. And while RP may be system-independent, 4e's black-box ability style discourages thinking out of that box.
This is highly DM-dependent. And if the DM wants to encourage thinking outside the box, the guidance and support given to DMs in 4e kicks that given in 3e up one side and down the other while keeping its hands behind its back.
There's no help in adjudicating odd interactions,
page 42.
no mental model of how something's supposed to work.
That depends how good you are at visualising powers. There's a huge mental model there of what's actually going on if you think the right way.
E.g. spells in 3e were often useful out of combat not merely because that was their intent, but also because their supposed functioning in-game was clear, and thus even if there wasn't an exact match with the normal scenarios (e.g. no enemy), you could reasonable rule on the effects. In 4e, that's harder - not impossible, but harder. If the fluff makes sense, you can actually use that fluff creatively.
And if you actually understand 4e, 4e has an incredibly strong and useful interlinking of fluff with rules.
In any case, I agree that plot balance is a laudable goal, I just don't think we should look at this as a zero-sum game: 4e's (plot) balance doesn't necessarily imply black-box powers without reasonable fluff
Is this going to be another discussion of
Come And Get It? Because almost all the powers do have reasonable fluff backing them. And I fluff my own as well.
nor symmetric class design - yet 4e does suffer from those flaws.
Symmetric class design has been
heavily weakened by Essentials.
And then there are lots of little design decisions that hurt believability without gaining simplicity or plot balance in return. E.g. the wishlist-based item distribution.
What that gained was an easier job for the DM.
The monster design that's dissociated from fluff.
You mean the effects based monster design that allows my dragons to behave like giant fire-breathing reptiles (or whatever breath weapon...) and not like spellcasters with wings and scales if I want to play them effectively? I'd say that's a better representation of the fluff than 3e ever was. It's just effects based rather than simulationist - meaning that what matters is that the monsters "play right" and behave the way they do in fluff, as they generally do. And I will say that monster design has got a
lot better over time - Monster Vault is a
massive improvement over the MM1 despite a huge overlap in terms of monsters covered.
Saves vs. forced movement - but only if into a pit.
The save also makes you fall prone. The assumption being that under almost all circumstances prone is worse than slid. It's the "clinging on by your fingertips" save.
Lots of interrupting powers - but you can't use em on your turn.
If you want to trade your standard in for an interrupt, I'd let you. It's like the "Throwing yourself prone to avoid forced movement into normal terrain" - almost always sub-optimal enough that it's not presented to avoid analysis paralysis.
You can shift when you stand up, but only if a creature is standing on you.
Using the monster's bulk as cover rather than simply writhing on the ground making a target of yourself. A decent fudge.
Solos with fundamentally meta-game bonuses.
Explain.
Disregarding size differences.
You mean on pushes?
These facts don't make a game
bad, but they do influence what kind of game it is. And 4e tends slightly more towards a game like magic the gathering, or say dominion (my current infatuation

) - a great, fun pastime, but you play it tactically, with cool combos and neat tricks.
I also find it better for RP than 3.X because there isn't the "Get a bigger hammer" syndrome. The answer to situations is think them through and solve them in character and in the world - not track down which spell in your spellbook was designed for this circumstance.
You don't use powers when their fluff is thematically appropriate, you use em when they're tactically sensible - usually, anyhow.
The art of power design - and something that Wizards normally succeeds at - is making sure that when a power is thematically appropriate it is tactically sensible and vise-versa. If this doesn't happen then the power is badly designed.
and because the focus is on the mechanics of powers, the player mindset is less likely to result in creative in-game applications of the PC abilities, and more likely to result in creative tactical applications of the game-mechanical effects.
And while on the subject
Symmetric design is boring. It's like rock-paper-scissors without the scissors - there aren't any meaninful choices anymore. ... Classes should be meaningfully different.
And you've just confirmed that you really don't have good experience with 4e. You might as well say that D20 took away all meaningful difference because everything is resolved on a D20 rather than percentile dice. My most recent three active characters are a Wizard, a Monk, and a Bravura Warlord - and they are
incredibly different from each other.
The monk is what the 3.X monk dreams of being but never quite succeeded at. A complete wire-fu master, backflipping all over the place and booting people in the head or sweeping their legs out from under them with his staff. Blink and he's darted half way across the battlefield, even to places you never thought he could reach on foot. Alternatively he runs across rooftops like a Parkour expert or sticks to the shadows like the best of thieves and can sometimes almost fly up walls.
The wizard is a wizard. Summons storm pillars and minature tornados to clog up the battlefield (or intimidate), and has some illusions and some hypnotic tricks. Magical, squishy, and effective if no one gets to him. He's every bit as magical as any 3.X wizard, whether or not there's Vancian casting involved. Out of combat he's a low level illusionist (he's only level 3) and an effective loremaster.
The warlord ... is
Leonidas. Other than that he wears sane armour rather than fights bare chested. He's a master of the battlefield, leading from the front to smash the enemy lines and bowl them over while looking out for his allies and either inspiring them to keep going or warning them of what's coming. His approach can be summed up as "Who Dares Wins" (although he's tactically ruthless in addition to this) and he's an expert at tempting his enemies by giving them half an opening at the right moment that if they take it it gives his allies an opening of their own. Out of combat he's alert, perceptive, and everything you'd expect from someone who leads from the front.
In each case the playstyle is completely different and the experience of playing them is very very distinct. And the rules support and encourage this distinctiveness. I therefore reject your implication that symmetric design implies that classes
aren't meaningfully different.
In short, everything you've just said tells me that you simply don't get 4e. And given the lack of help in the PHB I don't blame you. But your criticisms show problems with the presentation rather than the system.