The Shaman said:
D&D was founded on fantasy archetypes and that mode of thinking about classes persists. Perhaps it's maturity or gaming experience, perhaps it's something fundamental to the game of D&D - I don't have a good answer as to the reasons why. I notice this with respect to d20 Modern as well: Modern's base classes really does away with the fantasy archetype and replaces it with ability-based classes and actively encourages multi-classing to the point where there are no 20-level class progressions (i.e., everyone multiclasses at some point), yet I still hear players bemoan that they can't start off as a "soldier" since they can't take the Soldier advanced class until 4th level, perhaps unable to visualize a "soldier" as a Tough 1/Dedicated 1, a Strong 2, or a Fast 1/Charismatic 1.
Well, I think a factor in that is that in the medieval period, your profession was what you were. Family names came from professions in many cases: "Cooper" was someone who made barrels; "Smith" was, well, a smith; "Miller" was someone who owned and operated a mill. There were sumptuary laws, requiring people to dress in a uniform appropriate to their profession. The "family business" was expected to be passed on to the eldest child, and so on.
These factors are much reduced in the modern world. Society is more flexible and accepting of people choosing career options other than those of their parents, and even changing careers "mid stream".
I have long thought that D&D's class structure, in addition to reinforcing teamwork within a group, also better reflected the way a medieval society operates than a skill-based system. D20 Modern's differing themes to the classes reflects the changes in society between the medieval and the modern.
As to the original point, though:
I do not mind proliferation of classes, nor of feats, because I exercise selectivity. I review each feat or class before deciding if it will be allowed in my game. I like to think of it in comparison to an artist and the availability of various colors of paint. If you are going to paint a night scene, you do not need a lot of bright colors, but you do need many shades of blue, violet, and other dark colors. Likewise, of you plan to paint a sunny meadow, you do not need 31 shades of blue, but you might need a lot of shades of yellow and green. So, as a DM, I allow those classes and feats which fit the world I am running, and disallow those which are inappropriate.