ah, but with obtain familiar and theurgic bond, you can still have a full animal companion -- that definitely improves things a bit.
So, now you've got you + your AC + a handful of summoned creatures that all get to benefit from your bardic music. With bard1/druid2/evasion class 2/GW 5/FL 10, you get the highest level spells of both classes. While, yes, this is yet another example of "specific optimizing", but come on -- it's very straight forward and is "honest". I don't think that this PrC should be any less than a +0 -- full highest-spell-level casting in 2 classes, (almost) full bardic music, a full AC (with 2 simple feats); and all you are missing from 2 whole classes is a single class feature, that's it (granted, the class has to be supplemented with a couple of feats, but that is a whole lot less than the extreme acrobatics it takes to make many PrCs work well).
Just my 2cp.