No, don't agree at all: this is vintage Mann, and Cruise is fine.
I'm really sorry I didn't get to see this movie a second time while it was in the theaters here; it's such a gorgeous thing on a big screen. I saw nothing wrong with Cruise. I've always been a fan of his, but not of everything he's done. This is certainly one of the best. The idea that a hired killer has some kind of complex character that Cruise was incapable of conveying is hard for me to grasp. It's true that Le Samurai--a very, very different, and wonderful, kind of thing--presents the emotionless blankness of the professional killer wonderfully, but is Delon a great actor? He's just a great blank slate, and he moves suprpemely well in that film: there are moments of pure mime and his wordless grace and sureness are wonderful to watch as he slides through his motions. Cruise's character in Collateral is something quite different, though equally blank: he's a motormouth, jibing and challenging the naive dreamy Foxx, keeping up the level of menace so that he's safe--till his guard is down, he fucks up, and he's dead. But despite all the talk, Collateral is primarily a visual movie, all about the images, the camerawork, the light, the color. It doesn't really rely on the actors and it's not "character-driven" except in a very schematic sense. It's more an atmosphere and process-oriented neo-noir, and Cruise has to project a affectless blind energy and menace, which he does very well.
There's a lot of prejudice against Cruise; he has to deal with that every time he goes out. The notion that Anthony Hopkins is a great actor or that his Hannibal Lector shtick is great acting is another thing I find hard to countenance.
Mann did a similar thing with James Caan in Thief--not exactly a great actor, but a reliable one, a professional, Mann trusted him and made a great movie out of him (in that case, a more character-dirven one, because it goes into much more deph about the character's life)