I'm used to our group DPS buffs not working on ourselves, so that's not so bad (at least we benefit from Foe Requiem now!).

But I think Troubadour really ought to work on the caster...

There are workarounds though, I suppose. Say if the entire group needed mitigation from Magic damage, the Bard could use Minuet->Troubadour, and a caster could use Apocatastasis on the Bard, and that should do the trick.