This probably wouldn't help any of the people reading this, but could help other players yet to get started on the event.
The problem, as I experienced it: I logged on, saw there was a cool new event, checked the goals, met some goals, and went to check how close to a reward I was and... I was very far, because I was on a team with only one other active player, as the contested territory events I had casually played had always had matchmaking that kept things feasible anyways. So I left the team, leaving all the stars I had already earned while still keeping my progress, and started my own new team from the get. This felt rather demoralizing and I've seen others on here who lost more stars than I did.
What I suggest NK does (if it is in fact plausible): Make it so the first time you earn stars, you have to actively choose to "deposit" them into your team's current stash. You can either add your stars into this team you're currently on, or go to another team and pledge your allegiance and deposit those stars there. This way, people who jump in have the chance to make an informed decision about how they want their stars to go, without yanking them away from a team or otherwise breaking the balance of this event as already launched, with better alternatives hopefully prepared for next season. (And of course a warning pop up with a bit more of a description of how this all works.)
I will disclaim that I am hardly a power player of this game, nor do I know how the backend of the code works, so it's possible I've missed something important. I'm just trying to be productive as I do like the concept.