Meh.
Cleric? Could be a paladin build.
Sure, but since...
Paladin? Could be a fighter build.
...don't you think the cleric is more iconic than the paladin?
Fighter? Could be created without requiring the concept of a class.
Is it time for D&D to turn into a classless system?
I'm not even seeing your point here. Of course a classless system can accommodate fighting characters. D&D uses classes. If you're suggesting that I am suggesting that D&D should go classless- not at all.
As long as there are six ability scores, I'd like to see six classes, one based on each of the ability scores. Everything else is a hybrid.
Fast hero, strong hero, etc, like in d20 Modern? Viable, interesting, but not my bag personally.
Vampire is not and should not be a class, imho, ymmv.
See Heroes of Shadow. Like it or not, it is a class in the game. (Not that I especially like it, but saying "Vampire is not a class" is a lot like saying "Ardent is not a class." Should be is a whole nother animal, though.)
I guess my point is that, through D&D's history, class bloat turns into stuff like the warmage (I'm like a socerer, but better!), the runepriest (I'm like a cleric, but more fiddly!), the seeker (I'm like a ranger, only more naturey!), the wu jen (I'm like a wizard, only more Oriental), etc.
I mean really, if we distill it down, what character concept can't you build with the existing tools? What are these mysterious stories you can't tell?
You want to play a samurai? That's easy; play a fighter and call yourself Sapporo. You want to play a scout? That's easy; play a ranger.
There are a very few concepts that are hard to emulate from previous editions- the spellthief is the one I'm thinking of here- but really, I think you can get pretty darn close with a little judicious reflavoring.
If WotC keeps pushing tons of classes out the door, what they will end up with is dwindling sales. I haven't picked up Heroes of Shadow yet, despite being interested in a lot of it, because the cost : stuff I'll never use ratio is too high for my current lack of income. If they publish a PH4 that focuses on a bunch of classes from the Apple Pie power source and folks don't like it, not only have they invested in producing that stuff, they have set the expectation that they'll print a Heroes of Apple Pie or Apple Pie Power book- which are going to sell to fewer customers than PH4 did. Or else everyone accuses them of dropping support for the new stuff (hi there seeker and runepriest!).
Only if the PH4 sells well does WotC win, and I think this thread makes clear that a substantial number of potential customers don't want new classes. It doesn't seem like a good bet for business.