As a gen One’er, i will always have a soft spot for 2d, but i don’t think the 3d games are as horrible as most say (except SwSh).
2DHD style à-la-Octopath is where it’s at. Would have helped much the general vibe of the regions that has a lush world but where you are still free to “fill in the blanks” the way you want.
Besides, 3D is too much for a small indie developer like Gamefreak.
It aint the 3D thats the problem. Its the rushing out unfinished, uninspired corporate product because people will buy it anyway.
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.