Ah! I forgot Aspen is leaving on the 20th of March as well.
It seems that way because it's the leads/featured members who left/are leaving. But they still have awesome cast members remaining.
Van is great as Johnny. Libby's good as Extraordinary Girl. Jeanna's Heather fine as well. Jason's great in Theo's ensemble track and Miguel & Gerard are killing his solos. Mikey and Jennifer have been wonderful swings. Although Wallace is leaving, original Favorite Son, Joshua Henry is returning, so that's awesome.
Besides those mentioned above, Alysha, Andrew, Ben, Chase, Declan, Leslie, Lorin and Omar are still fantastic as ensemble & swings.
Justin, PJ and Krystina will do fine.
And you still have Rebecca and Stark in their respective roles.
The show's still amazing and you should still go see it.