>>49499796RB's overworld looks pretty good for Gameboy era, but their battle screen sprites were like, 50% bad. So it's why I say it was the closest point where GameFreak was ever "on par" visually when releasing to a console.
Yellow is obviously the best of both worlds, but not many games got to release multiple times like Pokemon did to fix their assets, so if you want to count Green/Red as the original version of Pokemon, then those monster sprites are terrible compared to Final Fantasy Legends.