I went
Warlord, mostly for the secondary effects the class has.
#1: A Warlord's "marital healing" is a big cause of Shroedinger's Hit Points, reinforcing the fact that hit points mean a million different things that aren't clear until you're healed.
#2: A Warlord's major ability is "pushing little pieces of plastic around on a map," which is a big source of the minis-centric focus of combat (and the combat-centric focus of the game).
#3: The space used for the Warlord took the place of space that could've been used for something cool -- like the Bard.
#4: "War*" overdose. Oh 4e and your idiotic naming conventions...
I've got no real big problem with any of the classes, but the Warlord is the poster child for several things that I don't enjoy about 4e, like it was presented solely to rub those things in my face.

It's kind of the same reason I'm not a huge fan of Dragonborn -- I see you're marketing ploy, Coast, but you've missed the mark, and you've misapprehended what I enjoy out of D&D.
The
rogue is a secondary offender, mostly for being all XTREME NINJA ACTION and no crafty thief trickery.
Everyone else is pretty okay. I'd prefer a knightly paladin to a god-powered beat-down factory, but I understand that the latter is probably more generally appealing. I don't mind wizards loosing the swiss-army-knife quality to a certain degree (spread that out! Rituals are a golden idea!). Warlocks are indulgent but inoffensive. Swordmage is some fun times.
But the Warlord made a huge crater with her impact, so I've gotta direct what little hate I have for any of the classes that-a-way.