FINAL FANTASY hasn't become stale. Its sales figures speak for themselves. And Square Enix has always been a company focused on innovation and every game we've gotten after FFX has had a sort of evolution of the game's gameplay. FF's I-III had standard turn-based; FF's IV-XII had ATB; FFXIII had its own evolution of ATB and so did its sequels; FFXV got more into the Action side; FFV7R has its own evolution of ATB.
Also, sometimes you need to address industry trends. Open world and action were a trend, so they decided to implement that on FFXV. But after FF15, SE decided to take a more... careful course of action with the FF7 Remake (Especially since it's the remake of an ATB game)
Also, sometimes you need to address industry trends. Open world and action were a trend, so they decided to implement that on FFXV. But after FF15, SE decided to take a more... careful course of action with the FF7 Remake (Especially since it's the remake of an ATB game)