In the past, the trend was adding RPG lite elements into action games after Zelda 2 became the blueprint. We are seeing that expand into stronger RPG formulas as the player base learns the basics and then demands a Dark Souls style of play.
What ? No no... Zelda 2 isn't the blueprint of anything, have you heard of stuff like Romancia ? Do you know the history of J RPG on computer ? It's far more complicated than that.
And the way you say it, it's like we needed Zelda 2 to appreciate Dark Souls... Wtf... And i'm quite sure Demon's Soul took a lot more from Amored Core anyway.
Now in 2017, hunting is the new thing with games like Monster Hunter, Player's Unknown, Evolve, Ark, Farcry... BOTW.
Well... I suppose there is some but... Even in BOTW i don't remember hunting that much to be honest. Hunting was always there anyway... (Why not talking about MGS 3 ? Or Ape Escape ? Is that too old for you ?)
My prediction is that Metroid Prime 4 will play on the bounty hunter role of Samus far more than in previous Prime titles. You are getting a taste of hunting Metriod in 2. We are going to see ways to trap or kill Metroids in many phases like in Monster Hunter. This concept came to me when seeing amiibo costumes for Nintendo games appearing in third party IPs. Nintendo is looking for the next big thing and they are not trying to be strictly traditional to please only diehard fans.
I don't think so, no... Do you know why ?
Because Metroid 2 is about finding Metroid and killing it in a very old school way, there is nothing new to this mechanic even if a game entirely dedicated to that is indeed quite original.
But since Metroid Prime 4 have nothing to do with the other team, i don't think it has anything to do with it.... Also, diehard fans would love hunting, i don't know what you are talking about.
... And I mean, if you want to see recent trend, Pirate seems to be more recent than "hunting" for exemple... Or Co-Op... Or Multiplayer (and Nintendo are on those trend)
Hinting is quite old in comparaison.
TL;DR : You need to stop looking to detail and see the big picture, you will see that your assumption is quite wicked from the start.