I feel they made the obvious translation rather poor, Eldritch Knight p-poor Swordmage and Battlemaster similar issues to Warlord.
Eldritch Knight wasn't really meant to be a swordmage. It was meant to be an AD&D Fighter/Magic User and a 3.X core Fighter/Wizard/Eldrich Knight (which was a patch in 3.X to make the AD&D Fighter/Magic User work). The swordmage was a far more specific class than that. And frankly the 5e Eldritch Knight was a better Eldritch Knight than the 3.X one (not a high bar).
And that may include the Defender Fighter . (And yes they eventually offered up the cavalier but its still rather easy for enemies to rush past him in quantity till maybe 18th level),
You're looking in the wrong place there. The 5e fighter gets extra feats for a reason - and the Sentinel feat makes up most of the 4e fighter's basic package; the ability to punish shifts (or disengages), the ability to punish people who attack people other than you, and the ability to flatten speeds to zero. It's a legit defender package, and you get a fighting style and subclass on top of that. It's a late start - but not that late given that 4e level 1 is about 5e level 3 and you can get this at 4th level.
Is it ever going to be as fun tactically? No. 5e is not that sort of game. But in this case it's not the defender that 5e is missing but the hordebreaker. On the other hand with multiple attacks per turn by default the 5e fighter is better at hordebreaking than a fighter that
hasn't focused on hordebreaking.
and it was an active design choice that they didnt want someone to be able to thrash minions the way a fighter with rain of steel and other abilities can)
It was an active design choice that they didn't want minion rules in the game, just "bounded accuracy". One of the many
many choices I disagree with.
Einstein was a creative genius (and actually pretty charismatic too dodging certain questions poetically)
So what? Just because some people have Int and Cha doesn't mean that some don't want one and some the other.
I would say 4e actively didnt at first want my wizard can do EVERYTHING to be a thing till Mearles took over so yes the developers wanted Arcane Striker to be farmed out into Sorcerers and Warlocks, I very much think on purpose.
The thing is that power selection means that you can't have a Wizard who can do EVERYTHING. You don't have the monster spellbooks. You can just make different wizard builds to do different things. And they didn't know what a controller was at first, just that they needed one and the wizard started too weak (although I agree it ended too strong).
Honestly if someone works out a striker wizard build that isn't a controller I don't care. I only really start caring if they can be a striker while keeping most of the control.
Just like I think my two favorite classes the Swordmages and Warlords were either impossible or a pain to build in a satisfying way in 5e and its very much seemed to be on purpose.
The warlord I think was on purpose. The Swordmage I don't see any malice in; it wasn't a PHB class and they had more than enough to do getting the PHB classes in there. Especially when multiple classes I'd consider far closer thematically to their 4e incarnations than to other editions (most notably the warlock, paladin, sorcerer, barbarian, rogue, and probably monk)