@beardalaxy The only ways I can think of to change the battle formula is to have Paper Mario style quick time events during attacks or something really unique like Undertale. Games like Earthbound have quality-of-life features like the rolling hp mechanic. Chrono Trigger has battles take place on the actual map with characters moving around during battle. I remember hearing someone mentioned about having items as characters, but to me that sounds a lot like the basic concept of Pokemon.
That's my main gripe with turn-based RPGs. They are way too content focused. They could all run on the same game engine provided that the engine in question has a good enough scripting language (which is probably why RPG Maker exists). The other gripe I have is that they would probably be better as action-adventure games if they actually have solid gameplay, but I don't know if anyone is welling to play a 40-hour action-adventure game.
@beardalaxy Well if it's something like (pre-BOTW) Zelda or Metroid, then you need 40-hours worth of unique items that allow you to progress throughout the adventure and you need to be really creative with said items. The only other way I know how to do it is just to have a complete open-world like GTA or the newer Zelda games where it is completely non-linear or has a bunch of side-quests.
@xianc78 i haven't played dragon age, but i know it is a pretty well received game that is also quite long.
@xianc78 oh, plenty of people are willing to play a 40 hour action adventure game. not many people are willing to make one, though. it's waaaay easier to make a turn-based RPG.