Seems to me that the "historical" bard just isn't a character meant to function in a small fighting squad, which is essentially what a party is. 4e, even more than 3e, defnitely focuses on every character being able to contribute roughly equivalently (which is not to say equally) in combat, and in order to get to that, you're going to have to do some tweaking to "guy who tells stories and sings songs for money". Makes a fine NPC, but to make him something that is as useful in combat as the guy throwing balls of fire or swinging a 20 pound sword, you're going to have to do *something*. Sure you can give him plenty of charming and information skills for out of combat, but in combat has always been a problem.
What 3e started, and what it *seems* 4e will continue is to give him magic and some "leadership" abilities (i.e. buffs, and now perhaps some tactical party maneuvering now that 4e has put that on the table).
Now "historical" might not be quite fair: there's no "historical" wizards or clerics (at least not ones that can do the kinds of things that DnD clerics and wizards do), but there are certainly prominent ones in fiction. But there's not really any fictional fantasy 3e bards (in the sense of singing in combat to hearten their comrades or throwing magic around kind of way). Well ok, those god awful furry-fantasy Spellsinger novels by Alan Dean Foster that I'm deeply ashamed to admit I read in high school when I didn't know any better.*
When I think of a fantasy bard, the only one that leaps right to mind is Marillion (I think that's the name) from the George R. R. Martin Song of Ice and Fire. He's on nobody's side but his own. Not much of a combatant, but damned good at ingratiating himself to the right people at the right time. That's a pretty cool character, but hard to pull off in the context of a party who's bread and butter is going into dungeons and killing things and taking their stuff.
*Alan Dean Foster: Hey, he's not Piers Anthony.**
**OK, OK, I read him too. Ugh. I need to shower now.
