Welp, I was looking forward to jumping back into this discussion after work, but it appears to have largely descended into insults and hyperbole, so I think I'll try and start up a new discussion.
One thing I actually found myself liking a lot in Samus Returns was the complexity of some of the later Metroid evolutions and boss fights; reminded me a lot of Prime Trilogy bosses. I'd love to see that return if this game sells well enough to guarantee 2D Metroid a future. The Queen Metroid fight in this game was really spectacular in my opinion; implementing a number of different features from the game that required a lot of thinking on your feet. I'd like to see more complex boss fights appear in future entries; I've always felt that bosses are one area that the Prime trilogy (and in particular Corruption) have handled better than the 2D games.