Lee, to answer your question, yes, the leader can be removed by a close encounter with a vortex grenade.
The mobile objective special character was not specifically created to make life difficult for anyone. We think it's going to add an interesting and exciting element to the event.
It's also going to make some other problems with scoring of the main, immobile objectives less painful and/or noticeable.
I really don't think it's going to be a big deal for those of you who don't feel like focusing on it. You can just tuck him away behind friendly lines and hope for the best. It shouldn't ruin your day or anything. If it does, I'll have a box of tissues on hand to pass out.