Making the dragon shaman more powerful, or putting them in a context that's well-suited for them, doesn't really help, because their problem was never power in the first place. Their problem is that they're just boring. If you're aura-ing a party of 5 and shooting poorly with a crossbow, or aura-ing an army of a hundred and shooting poorly with a crossbow, either way, you're not doing anything meaningful. Any aura on that army will easily make you the most powerful member of the army, but it's still boring.