I completely understand the concern about Gear Up. It is flippin insane. Lol imagine the fun if an opponent slipped a Nullify on you and you tried Gear Up thinking it was just a curse, it'd be an instant table flip
As Kharhaz said the play test for Gear Up was intense and I can remember several different arguments being made for it. I'm actually delighted how it eventually came out.
There's a few other cards hinted at already such as the new goblin. Listen to the spoiler video and you get the gist of it: You can cast more than one with a single action. That's obviously going to be a new strategy right there as you can swarm ridiculously fast.
One thing to remember about formations is they're all dirt cheap to cast and cantrips. So there isn't a single reason not to have one out at any given time if you have even one buddy.
