Yep I agree with Mortis. Bards survive by running away and/or casting GV (Unless you're Mish with 130 AC haha). I use healing circles and spam mass cure serious wounds on the tanks that are up front. Placement is key, you have to be close enough that epics and healing circles are useful but not so close you're getting aggro from the mob.
FWIW mine is 30 base Charisma, and the rest goes into Dex and Str to help make checks. I don't even bother with Phantasmal killer or Dirge because my DC is so low. Casting mob-focused spells like Amplify and Bestow Curse are really secondary anyway, to your primary task of keeping people alive and active.
Bard has turned out to be one of my favorite classes. Your build looks solid and I hope you enjoy it.