Not to be snarky, but who in the hell ever said bard were terrible?
Sure the hell not be me.
Take the Inspire Courage setups. +1~+2 from Bard alone since you probably wouldn't take your effective Bard level past 8. +1 for a Natural Horn, +1 for a Badge of Valor (only 1.4k for 3/day), +1 for Song of Heart picked up by trading Fascinate out, +1 for Inspirational Boost by expending a 1st level spell slot, then double the entire bonus for Word of Creation. The easy +12 moral bonus to Attack and Damage turns even a simple commoner into a deadly machine. And unlike level 20 builds where you may handwave things away as "oh it's awesome cus it's level 20", you can hit this bonus by level 8. In fact, you can do it in E6 if you wanted. This isn't a capstone trick but rather one you've had the entire time.
Dragonfire Inspiration turns your Attack bonus into d6s of Damage to use against your enemy. And a Crusader dip not only gives it's own fun Martial Adapt bonuses, but at no IC loss you can pick up Song of The White Raven which lets you IC as a Swift action. In a single round you can use the standard IC and Dragonfire versions. Lastly, something like Lingering Song persists IC's effect for ten rounds after you use it, meaning you could IC/Dragonfire as a Swift action and Full-Attack every round of combat while the entire party benefits from your buff.
And are you short of party members? No problem. Since Song of Heart can be picked up for free, Words is 6th level+, and Lingering Song can be replaced by Harmonizing. You're pretty much only looking at Dragonfire being picked up at level 1. With Human or Flaws you can pick up Greenbound Summoning by going Savage Bard. Heck, pick up Augment Summoning too. Greenbound Animals are fracking insane
before you used IC on them. Afterwards? Your army of plant-bears soaked in acid tear through the side of a mountain to "surprise" a dragon so you can afford a new cloak.
Finally, spells. the Bard's spell list is full of insane skill boosts like Sticky Fingers (+10 to slight of hand), Improvisation (+1/2 cl to any skill), or Glibness (+30 to bluff). You can get your Charisma to Saves (ruin devler), Blind people as a free action (blinding beauty), half all melee damage the party takes (empyreal ecstasy) and so on. Bard also gets Nixie's Grace and Snowsong, among other things they allow the Bard to obtain +6 to his Charisma no other character has the means to do. And not only due your Save DCs get higher than most other casters (try 50+), Metamagic Song can be used to give you a method to Persist without having to PrC out into Incantatrix.
P.S. Sublime Chord, A Bard-Only PrC, grants Sorcerer/Wizard 9th level spells. In case you thought the 6th level cap was his only weakness.