I do think an embrace of other styles of game,from art style like the 2.5d game Octopath Traveler or game play with the mystery dungeon, Ranger series along with Pokemon Conquest , would help breath new life into the series but that just goes back to what you've pointed to as the real issue; Rushed and Cynical games.
I would love to see the mainline games experiment more with different artstyles. Like you said, it would make the games feel new and visually exciting again. But yeah, I don't know how that's going to happen with the current release schedule.