Question

This can be done, but I would consider Balrog and any other future skill-restricting bosses before doing that. In reality, the skills you would get in place of those would be Iron Body and MP Recovery, both of which are less useful that the rest. However, if no higher skill-restricting bosses are added, Brandish could completely be skipped. I myself won't be taking that chance, but you on the other hand may not want to fight Balrog or any boss of that sort. It's how you want to play your character.

Not to mention having a DrK with you on bossruns provide the same def buff and an additional m def buff for the party, iron will, that does not stack with iron body.