I know I'm late to respond, but I can agree with that Super Castlevania 5 idea, I would be the equivalent of most peoples Half Life 3 crazy if that happen.I agree with just about everything you posted. The only 2 things I disagree with are:
1) Mario 64 is only good, not incredible.
2) Castlevania 1 is easy, I half agree with this, for me Castlevania 1 is easy, Contra is easy, double dragon 3 is easy, but thats only because I have played these games so many times in my life that they are ingrained in my head, as Castlevania 1 is ingrained in yours, but watch someone play it for the first time and I think you will see how challenging it is for people who did not grow up on it.
I also am not sure that classic castlevania is better than metroidvania is an unpopular opinion. I do love the metroidvanias but I think there are tons of people like us who would love nothing more than a classic castlevania game. My dream game is a Super Castlevania 5, A game that has all the mechanics of 4 but with all new levels and modernized graphics, keep most of the soundtrack though, 4 has some of my all time favorite game songs.
I can see where you are coming from with my CV comment, I actually still struggle with Contra, without the 30 lives code at least, probably because I did not play it til later in life. I feel as if Contra is 100x harder than CV 1 haha, as you say experience has alot to do with it.

