My thought is you would add a mission type that would give you permanent access to old event formations, each mission would give a different formation which you could run free plays on and give a small chance at old event silver chests, and an even smaller chance at event jeweled chests. The way missions are built now it will take newer players years to get crusaders and gear this way once they got both crusaders they would be able to unlock the formation. You could even remove gear missions in lieu of these missions. It would also give older players more formations to play with and the advantage of not having to get the crusaders just the formations.

Thanks for listening :)