I agree, you will spend your TP faster and if everyone else hasn't gotten as much of an increase you will bleed dry. Everyone needs that 10% increase for it to proportionally die at the same length.
Making the classes/jobs self sustaining isn't a good fix for that, or else BRD buffs become irrelevant. There needs to be class dependency, and that's also why half of the battle classes can't provide their own damage debuff(WAR provides for WAR/PLD, DRG provides for BRD/DRG, BRD provides for THM/SMN, and MNK is the outlier[but that's probably why DK lowers INT, too]).
Class dependency is a good thing. It's only a problem if you can't function without that class -- And all classes currently can function without the need for another class entirely. However, having those classes helps, a LOT--And that's a good thing.
