Imaro
Legend
There's a trade off with classes - you get a significant level of confidence that the party's on even footing, which gives you easy paths to encounter and adventure design.
To get that, you need to give up some flexibility.
If you want infinite flexibility, you probably shouldn't be playing a game with classes. If you are playing with classes, you ought to be ready and willing to either wait for someone to make up the class that fits your concept exactly, make it up yourself, or be willing to make a few compromises.
I don't think anyone asked for "infinite" flexibility. But I do think a class system should be robust enough to cover the variations on the roles that particular archetypes encompass. This can be done in numerous ways such as making the class abilities generic and broad enough to fit with the varying iconic roles of the archetype (like a class in Basic D&D) or giving the player the option to customize it with decision points in order to "choose" which iconic role he wants his archetype to represent (feats and alternate class abilities in 3.x). However I think basing your archetypes around a particualr role leads to an unnecessary loss of flexibility overall.
Again this wasn't a problem with missing classes it was a problem with, IMO, heavily tying archetypes to roles... in fact I would argue that the classes in 4e (as far as discussion goes) are much more associated with the role they serve in combat than any archetype they may be representing.