Sunic, how many times have you berated people telling them they should be immune to as many attack types as possible? Isn't immune to mind affecting one of the stock standard immunities people should have? If so... doesn't that make your Bard completely useless in the very parties you've discussed, since being immune to that means Bard song does nothing?
Plus, if it's a baseline competence issue, we usually don't say "oh, you need a Bard to help you since you can't do it on your own." What if there's no Bard, a class often called a 5th wheel? There's still a heck of a lot of folks who use the standard "healer, arcanist, beatstick, skillmonkey" concept, which with a Warblade in a T3 party would be Crusader (or Binder), Beguiler (or Dread Necromancer), Warblade, Factotum (Bards can't detect traps or anything). I think you just failed at what you claimed was standard.
And stop with the "stick together" thing. Real scouts don't split the party, no matter how many times you might think otherwise. Also, running around singing alerts enemies to your presence. Maybe that's why monsters all know your party's capabilities... they're a freaking marching band. If your monsters were at all competent, they'd all get reinforcements the moment Sergent Pepper's Lonely Adventurers Club Band showed up in the dungeon and just ambush the (scoutless) party with everything at once. In my games, the players tend to kill the monsters that might know what they can do, so none of them run off to the girl's room to chat later and spread around what the party can do. Plus, they kill things fast without giving them time to get help.
JaronK