Well making a game like Final Fantasy 1 to 6, Is possible to make if you have RPG maker. RPG maker is easy to use that even a child can make games with it. If you want to make a game like 7 to 15. You will be needing a background in programming and coding.
If I will be an Employee of Square Enix, for a change from the Futuristic ,Steam Punk and Medieval settings, I want to see a Final Fantasy game set in 80's. 80's theme is popular these days. 2 of the most popular shows on Netflix is set in the 80's.
I want a cast that looks like they are from the 1980's though they will have futuristic weapons. Imagine an adventure on a futuristic looking 1980's.
No, I would leave it to the experts like Square Enix- the company that makes Final Fantasy, but they do have a program to make your own video games. Its called RPG Maker and they say you can know nothing about programming, and just use your imagination and their software to bring it all about.
According to wiki, hundreds of games were created to date, though none of which I recognize. If the tool/engine doesn't require much programming knowledge, then it most likely is fairly limited in its utility.
I don't think it's a good idea in general, to try and create a game or any other complex app with little or no programming knowledge, if you want to actually profit from it.
If I were to create game from the scratch then I'd make the FF mix of injustice 2 and the FF's own way of dealing with the game flow. I think summons are good. But they need to add some interesting stuff like mystery, puzzles and the fights like the injustice. I think it's possible for company but they don't work on that part much.
Undertale does not look like something made with RPG engine. It seems to be lot different though. Unity's 2D and 3D engine makes it easy to mix the genres. And so it kind of interesting to see how the game developers work on those and finish the final product.