I wonder if this mythical "difference" I keep hearing about is effectively a "gearhead" vs. "casual player" distinction.
The gearhead notices things like "poorer baseline damage" and "possibilities for mobility" and specific power tactics and how a playstyle can make something "inferior."
The casual player just notices that whether I have a dark pact with unpleasant forces, or a bow, I'm doing the same "point and shoot and effect" mechanics.
But this means that the casual player isn't just a casual player, he's an inattentive one. So inattentive as to be unable to tell the difference between firing two arrows and
an attack that makes you invisible to the target. (Or one that punishes them if you get hit, etc.) Yes, Eldritch Blast is like a ranged basic and pretty similar to almost any other ranged basic. But if you can't tell the fundamental difference between Eyebite and Twin Strike you aren't paying attention (or the DM isn't). And that's without getting into the
other pact at wills which are even more different (other than the darkpact one). And for a Darkpact Warlock, the matter of soul fragments swirling around the body and punishing people for hitting them is non-trivial.
This isn't +1 gearhead stuff. It's fundamental. It's near-ubiquitous. And if casual players aren't picking up on even that much, I wonder what they
are picking up on.
Maybe you gearheads see a glaring and obvious difference, and people who are less hip-deep in mechanical gristle don't see it, because it's not relevant to them.
And even people who don't see numbers should be able to tell the difference between
invisibility and a second arrow. Or between
automatically burning the enemy if he gets closer and a melee attack to provide a distraction to slip out of combat (to pick the only at will that really complements Twin Strike for an archer ranger).
It's pretty clear to me that the 3e warlock and the 3e rogue were very different characters, and different types of roles could be played within those mechanics.
It's not so clear to me that the 4e warlock and the 4e ranger are different. Having played and DMed for both, I couldn't always tell you from their combat behavior which character was the one with his soul sworn to hell, and which character was the wilderness archer. They didn't act much differently
What the hell sort of Warlock did you have? That said, for all the lovely fluff on a Warlock, it's a real gearhead class if you want to get much out of it.
I wasn't impressed with Polearm Gamble, and it's Paragon level, like the two reach-focused PPs. There's a feat to let your Close Weapon attacks use your weapon's reach, but it's Epic. That's what I meant about the builds being late-maturing. A 3e reach fighter could have some meaningful functionality from 1st level on.
Oh, and Tide of Iron: how does the galive-wielder get around the shield requirement?
Reach controllers are mostly Paragon and there's much more than Polearm Gamble. For a proper reach controller you need:
Longarm Student (Heroic tier feat - because you're right, you can't Tide of Iron with a polearm - but Longarm Student adds a push to cleave).
Polearm Gamble
Polearm Momentum - anyone you push 2 squares with a polearm is knocked prone
Heavy Blade Opportunity - Use an At Will (i.e. cleave for the push) on opportunity attacks
Spear Push (or just a ring of the ram) to add a square to the one square push on Cleave.
... And the enemies go flying whenever they try to get anywhere near you.
But honestly, you don't
need this for a basic polearm controller. Marking is a debuff. Mark and push - and then move elsewhere. Or lure the enemy in with a mark. You have meaningful functionality from marking + reach alone.

My point is that yeah, classes in 4th are quite different, but in 3rd they were MORE. For most 4th edition players
the way they are different now is a feature, because of gamestyle and balance and other things they like of 4th edition.
Really? So a sorceror was more different from a wizard in 3e than 4e when they had the exact same spell list? And the wizard's memorised casting was functionally no different from clerical casting (other than the spontaneous heals and the almost irrelevant turns). Did they feel different? (If they did, then where's the 4e issue here?)
And before fifth level (and the Pokemount) I'll call the 3e Fighter, the Barbarian, and the Paladin less different than a brawler fighter, a battlerager fighter using daily stances, and a sword and board/tide of iron fighter with a warlord multiclass feat and whatever the L2 Endurance Skill Power is called.
Now I'll gladly accept that spellcasters were different from non-casters. And some of the classes that showed up very late in the day (Warlocks, Artificers, Magic of Incarnum, Book of Nine Swords) were different again.
But I explained above how in 3rd edition the system and the gameworld made them different. For someone this kind of attention was not relevant, but for ME it was.
And for me there's far
more difference, precisely because you
don't have to look at the numbers. You look at what's happening on the map. Thunderwave is not Burning Hands and a single glance at the battlemat can show the difference in a way it can't between Burning Hands and Fireball. And Tide of Iron is not Brash Assault - and both say a lot about how the person with them function.
And WotC completeli FAILED to reproduce this kind of attention in 4th, or at least to put an accent on it. Of course, this is, again, a feature for most, but for me is not.
So, you must accept that people can feel this sameness. So:
Blink Elves ---> Good.
Samey Classes---- > Bad
Mechanics of the Gameworld not Helping -----> Bad
And I once again ask why you say the classes are the same and think that the magic users or the non-magic users in 3e are not. (Or did you really expect 4e to come out with all the variety in 3e in the very first books?)