Sometimes I wonder if a lot of support skills would be better served if TP were, well, still a resource (or MP a resource on non-casters and made more diversely a one on classes that already use it). At that point you could have Mantra, Brotherhood, and a couple forms of burst direct damage consume it, so you aren't effectively "taxed" just for having access to Mantra/Brotherhood, but instead in proportion to their use.

...I'd still revise Brotherhood to just increase all skills' potency by 5%, though, instead of letting it lock us into physical comps.