As a Paladin, I get goad rather often. As a DPS, I neither expect it not receive it very often. As a Ninja, I'll dole out goad in order lowest to highest TP and then by class of tank > DPS. You know how many times I've used goad on a Bard? Never. It's really not been an issue. Smart players know how to manage their TP, and use invigorate wisely. Those who don't usually slap on Paeon and save me the trouble.

Truth be told, if a ninja uses goad on a Bard it's because there's literally no one else in the party who needs it. I'll always prioritize those who hit the heaviest and use TP the most before the support classes. Bard has a good AoE skill which use zero TP, so use it.