Chrono Trigger is widely considered one of the greatest JRPGs (and games) of all-time. There have been JRPGs since then that have been similar in style to Chrono Trigger in one way or another such as Radiant Historia & our own Cosmic Star Heroine, but even when people like these new attempts, the general consensus is that they're not on CT's level. What would a new game need to do to match Chrono Trigger for quality? What attributes do you must care about in a CT-style RPG?
Graphics:
Here's one thing people may not get when they make these retro-like games in an attempt to capture FFVI or Chrono Trigger vibes. At the actual time of their release,
they were not retro. When Chrono Trigger came out it was one of the best looking video games ever. Cutting edge. The same for Final Fantasy VI, the same for Final Fantasy VII. Like it or not, the top of the line graphics played a part in CT's legacy and how it was received at the time, and has helped carry it on to this day. (Again, same with FFVI and VII).
So when a "retro" game is made to capture Chrono Trigger (Square has been guilty of this themselves with I Am Setsuna), they make the graphics in the old school style, but forget that at the time that game's legacy was made it was not "old school."
To capture what Chrono Trigger brought to the table, one of the major elements is you need to deliver one of if not the best looking RPG ever, because that's what Chrono Trigger was when it came out.
BEYOND GRAPHICS:
Time Travel (or how I learned to love the Epoch)
Chrono Trigger had a lot of very unique elements than even Chrono Cross did not try to emulate. No. 1 was free time travel, at any time, at any moment, to any various periods in history. The ability to go to one location and have it be modern, go to that same location millions of years in the pass and see what it was like, or visit the exact same location in post apocalyptic times - CT time travel just added to the amazing journey/experience and it hasn't been recreated yet. The sheer amount of time and resources it would take nowadays to make one world five different ways, and write a story with a cohesive time travel element (Avengers Endgame joked about this, how movies always fuck up time travel), very few could do it these days, and do it with the budget needed to make it similar to the same AAA graphic experience CT was in 1995.
Battle system
Again, at the time it was incredibly unique. The team up moves were amazing, the ability to actually SEE enemies before you engaged them was a game changer. I don't know if many games did it before Chrono Trigger, but certainly after it started an avalanche, and it is pretty much the norm now. To the point where now if you make a JRPG, it's expected. Back then, it's one of the tings that made Chrono Trigger stand out. It wasn't a "chore" to play like a Final Fantasy because you could avoid random battles better. This meant Chrono was looked at as more "fun" than Final Fantasy and in addition to the amazing graphics thus was more accessible to people who wouldn't normally play JRPGs.
New Game+
Every game has new game plus these days. Chrono Trigger invented it and named it. But again, much like the thing about AAA graphics being lost on a lot of people in terms of CT's impact, it's also lost on just why NG+ was so impactful for CT, and why putting it in any random game doesn't matter as much. Chrono Trigger was a bout time travel, so when you started up NG+, you could literally time travel directly to the final boss and kill him! You can literally do this at any point in NG+!
The idea of New Game+ was made for Chrono Trigger because of it's time travel aspects, and it's never been implemented better in a video game since.
Miscellaneous
This goes without saying, but amazing story, characters and moments. The easy part, right?
