We're just a combat and fetch specialist, nothing wrong with that, we're not called upon to look at the future or navigate politics the way Krile and Minphilia do. Fordola may be an inferior combatant to us, sure, but as I recall she was unbeaten until we arrived did put up a fight against us. Ardbert and co would have beaten us if not for Urianger's betrayal. And you conveniently leave out all the times Zenos canonically wiped the floor with us. The WoL might one day take up strategy and may even be good at it but we're not there yet, that's still Alphinaud's purview.
Similarly there's nothing wrong with our presence inspiring NPCs, renowned individuals have that effect, you need only look through history to see that. A rumour of a successful tactician arriving or the flag of an elite unit showing up can turn entire battlefields, sometimes without the actual person or unit in question even being there. I'd bet if a Garlean force was losing badly and Gaius showed up whether alone or with reinforcements, they would be inspired to fight harder too.