Isn't it crazy to think every mainline Metroid entry is going to be on the Switch? Then throw in a remaster of Prime, and you got Metroid fans just feasting this generation. Pretty sure Prime 4 is going to be a cross-gen title when that finally releases.
With the Prime remaster releasing, I'm betting Prime 4 will be revealed during the Summer Direct. Especially if the rumors are true that the Prime remaster has been finished for who knows how long. Timing can't be a coincidence.