Lasswell definitely has a niche in that ice SAM is rare, and if your wind options are limited he might be able to help.

Rain and Fina are more common ground but still, awakening/sync can very quickly be "there's my healer, or there's my second/third DPS."

Like, on paper Minfilia is a lot worse than most of my knights, but with her fast cast and particular buffs I actually have been using her a lot for the missions.