Lots of good suggestions in here, and I agree it’s going to get exponentially harder to simply cover (13 / 450) new 5*'s if they are going to be released so quickly.
Which comes back to the very long give and take this game has had, and I argue all the time: if you are going to increase release rate (or any other resource needed) - you, the devs, need to equally increase the drop rate to acquire these resources.
To give a few extra shards as rewards and then increase the release rate quite a bit makes all those “Look, shards, new ways to get 5*'s bigger and faster!” a few months ago look very, very inaccurate.
Need more LT’s, more shards, more feeders, and very likely - a higher 5* rate out of all tokens.