Although again I don't think Duskblade, Factotum, or Beguiler clearly map to a given "role" in the game, especially using the 4E/computer game definition of such.
A Beguiler can debuff a group of targets, a single target, as well as buff himself or his allies. The Controller class role, and I may be mistaken here since I'm not all that up on 4E, really does the first two, and even then really only emphasizes the first 1. There's not a one to one mapping of role to class in these 3E classes. In 4E, there is explicitly such a one to one mapping. And, from what I've seen, that colors the entire class feature and power design.
Take the Crusader. My gut instinct would be that he would map right into Defender or Tank. But, as a player in 3E you really get to decide how much emphasis you want to put on that role. And, a Crusader can very credibly serve as a controller (Thicket of Blades + AoOs, along with the eventual White Raven Hammer and Shield Counter maneuvers), leader/buffer type (White Raven, healing), or striker (Devoted Spirit, Stone Dragon, possibly some Channel the Storm shenanigans). And, then there are other, more complicated mixes like the Bardsader or Ruby Knight Vindicator.
So, sure, while it might seem that the Crusader lends itself towards one kind of party role, depending on your feat, multiclass, and maneuver choices, you can straddle or fill many others.
I did not feel the same sort of flex in 4E. I played a 4E ranger on several occasions, and I did not feel that there was a couple of feats or a power I could take to, for instance, do some off-tanking or party-supporting. And, this was with all the optimization forums at my disposal. I was, with some creativity, able to make a lithe, mobile melee attacker who could knock down enemies and therefore disrupt their lines. That was enjoyable, but it's pretty clearly the role of the 4E striker, with a bit more of a tactical rather than DPS emphasis.
This, is, I think, what the MMO critique amounts to. And, it doesn't help that the game doesn't have multiclassing or really prestige classes of the sort that 3E does b/c that removes a big set of options, as illustrated above.