I had that card as well and attempted it, after capturing Leah. So I sent in Boba and Vadar to do the deed and he pretty much comited his whole force to stopping me. So I didn’t succeed but effectively wasted his turn. So then I basically bluffed that I was going to try that again with the carbonite card to take her out of the picture. So again he basically wasted his turn while I only used a couple of leaders on it.

My one big disconnect is that there didn’t seem to be any risk at failing an attempt, other then a possibly wasted action. But since you only fail if you are opposed it nets out. Also some of the Resolve cards felt way more powerful then the attempt ones so I generally used them or just moved troops around since subjugating a planet seemed to prove really effective.