None. I wish people would make new games and stop riding on other people's nostalgia. The originals still exist, i can still play them easily, and they're always better than the rehashed fan-games that come out 45 years later.
I know it's not that same era, but the original Legacy of Kain Soul Reaver. It was so ambitious at the time but the first generation of consoles wasn't powerful enough to realize it. The Dreamcast version is far better, but it still needs a modern treatment, the controls are awful by today's standards.
I think Comix Zone has always been due for a revival. It was the coolest thing on the planet in 1995. it has a rich hand-drawn art style that could flourish without pixel art, and it's a frustrating game in some ways but has a richness to the play depth and puzzle systems that could be greatly iterated upon. So worthy of a return in the hands of a super creative director.
I remember something about this unfortunately not being great when I tried it at an arcade show a few years ago, but...
I do honestly think 3D orientation might be a good thing to try in beat-em-ups (as blasphemous as it is to say that.) The typical technique of cheating the flat sprites to only engage on one plane is classic game design, but it also always felt cheap and limiting, as you waited for enemies to come down into your flurry of attacks. This Turtles game is a promising development IMO that the characters CAN fight up and down as well as sideways, but they still turn back to their line forwards/backwards for the most part rather than having independent 360 character movement (ala Powerstone.) This looks like it plays like a 2D brawler generally, but because it has 3D orientation sometimes, you can't get away with spamming so easily and you don't have to walk into attacks that you know ae going to get you socked.
...In general, everything has to play together when a classic franchise comes back: the graphic style, the gameplay choices, the stage design. It doesn't help that classics were classics because the best in the business at the time tended to work on them, and often the same genius (or even simply the same working conditions, as sometimes the "genius" is something that even the creators don't understand and can't capture in a sequel,) doesn't exist out there anymore even if the tools for making games are much more available now. So I do personally welcome revivals like SoR4 and Turtles by Raw Thrills and Double Dragon Neon, but like anything else, they've got to be good.