This is, I dare say, the best attempt at bringing an old class to
4E that I have seen so far, really. Most stuff I'm seeing are people trying to make
4E versions of old editions' classes without trying to adapt to the new mentality of the game, but this one feels like
4E.
I didn't read through all the powers (or spellsongs as you called them) but overall I could tell you took the other leaders' powers as examples on how to balance. And at least the heroic tier ones (the ones I looked into) looks balanced and interesting enough.
Now a couple observations corrections and/or suggestions:
Trained Skills
-Any particular reason you took Streetwise over History? For me at least, history makes alot more sense since, well, when I hear about bards the first thing that comes to mind are the stories and tales they tell and such.
Implements
-This is probably implicit in there, but fluff-wise it would be cool to explain that, if for instance you don't use any implements you are actually singing a song or somesuch... Not that this is any important...
Bardic Knowledge
-Sorry to say this, but this one looks rather useless, lemme try to explain why. Most other classes (leaders or not), have stuff that gets a bonus either equal to one ability mod (ie. Combat Superiority, Healer's Lore, Implement Mastery, Commanding Presence (to some extent)) or they go even beyond that and instead give bonuses based on level (hunter's quarry/sneak attack/warlock's curse, kinda of an unfair comparisson though I have to admit).
Also, it's worth to mention some of the stuff that gives a flat/static bonus to a given stat (Weapont Talent, Combat Leader).
That being said, what good is a +2 to knowledge checks compared to all those other classes' features? I'd think that since it has almost (if not at all) no impact in combat, and as such it should either be a bonus that increases with tier +2/+4/+6, or even a bit more extreme, +1/ level (or +1/2 per level). All else fails, make the bonus stat dependent (Int probably).
Cantrips
-I like the idea of having cantrips, I just don't like the idea of getting them from the same list as Wizards, even though Prestidigitation and Ghost Sound fits perfectly for the Bard. When you "steal" something from other class it gives me the impression you're trying to be someone else. I think they should get their own set of cantrips.
Bardic Song
-I really like what you tried to do here, and also where you're coming from. But having only 2 Songs available "to the rest of your life" since level 1 doesn't seem right to me, there should be a ways to learn new songs.
Also, a couple notes on duration:
On fascinating song you used "until the end of your next turn (save ends)". This doesn't really exists on
4E, you should pick either but not both. (p. 278 PHB)
Some of the songs could use a "Sustain Move/Standard" clause (not sure which), it'd make them interesting, representing that you keep playing/singing maintaining the effect.
I like the way you tried to give some of them some kind of synergy with Healing Hymn (and btw, that's a nice name for the ability you got there), but as much as the idea looks good I'm not sure it delivers, maybe each of those should get an exclusive "conditional" clause like Inspire Courage would receive an extra +1 for one round, while another song would get something else different.
Anyway, enough for now.
Great job you did there.