I feel like I'm taking crazy pills for not shitting myself over the Metroid Prime 4 announcement, but a part of me just thinks that it was probably something that was rushed to greenlight internally so they could announce at E3.
Reminds me of Shenmue 3 and FF7 remake, and I'm sure I'm forgetting a lot of others. I feel partly we need to show that we're excited about them making a sequel but also to consider having something to show at e3.