One of the most notable departures was last Friday: Rick Houlihan, the guy who basically invented (or at least popularized) DynamoDB single table design. I can't quite figure out if AWS is asleep at the wheel while these people leave, or MongoDB is pulling out all of the stops. Maybe both...
I think Rick would be the first to admit he didn't invent DynamoDB.
Massive exodus going on at AWS right now. VP Raju Gulabani leaving AWS, basically the godfather of databases at AWS.