I am really really surprised by how obssesed folks are with Team Cherry developing a Metroid Game.
Hollow Knight is its (really good) own thing. As I have said in this very same thread, having created a fantastic Metroidvania videogame does not automatically mean that you are going to nail a Metroid game. The exploration pace, the movement, the mechanics... it is all different and as others have said you would also have to count with Sakamoto guidance.
If you have some love remaining for a series, as I think it is the case of Nintendo with Metroid, you don´t want to have an endless numbers of developers touching the series because it becomes some sort of Frankenstein. You want to invest, develop a relationship of trust with a company, to create a series of videogames with certain identity to try to make people love the series (again in some cases). I don´t know about sales numbers, but I am pretty sure Nintendo was delighted with what Samus Returns is as a videogame, as well as the majority of players and critics are, so I think Mercury Steam will definitely have another shot.
The most absurd thing of this discussion for me is trying to translate the Hollow Knight visual style to Metroid. Look, those late eighties-early nineties artworks are no longer Metroid, the series have had a "realistic" visual approach since Metroid Prime, and that means since 20 years ago. On the other hand, if a 2D sprited Metroid videogame were created, it would have to compete against a pile of indie videogames (many new players don´t know the series) that have absorbed that visual style and the Switch capabilities would be severely underused.
Also, you have to read here that "2.5D videogames" are ugly. Welp, I guess you also think that art direction has nothing to do with a videogame being ugly or pretty.