Looking at Saguaro Sentinel, Pin Missile is supposed to be their option vs. flying enemies but at one shot every 2d4 rounds and losing a big chunk of your abilities it's not really much of an option. That combined with it being a mandatory AoE even to attack one flying enemy just ends up feeling... wasteful, I guess?

It would be nice if there was a single-target version that recharged faster and didn't use all your spikes at once. (Maybe stripping Needle Arms and Thorny Grasp from one of your slams each time you use it.)