I totally understand the frustration of not hearing anything back but I'm happy that you've gotten multiple offers! While I'm sure that it would be cathartic to send that email, adcoms talk and I'd be warry about putting something into the grapevine you might not want to pop back up in the future. Why not bask in the glow of your existing offers and start planning some summer trips? That seems like much more fun
For those of y'all who get into Miami, please pay it forward and ask the adcom to change that policy. You guys have the pull to make that change! Also, CONGRATS!