This framing seems really disingenuous, including Vengeance as necessary? That's just loading the deck. Vengeance is immanently skippable. I'd be more prone to believe assault. You're at least providing bonuses to your pets with assault.
But yeah, every build has to make power choices. I had to drop Oppressive Gloom from my Dark Tank because I decided I really wanted Whirlwind. I would take Leadership on every build if I could.
But this, you don't even say what your secondary powerset is and you already decided that it's better for your build to have Group Fly, Fold Space, Tough, and Weave, to say nothing of their prerequisites. That's not how builds are made.