My instinct is to think s3 was more greebly, but I think the G1 cartoon aesthetic in general is relatively smooth, s3 included. S3 just had the occasional episode with more of a budget and/ambitious animation that tried to emulate the movie vibe a bit more than usual, but with gratuitous shading/etc lines rather than greebling. Some shots of Galvatron in TRoOP are just festooned with em.
Kingdom Rodimus was okay with a very "how did you miss THAT" vibing altmode, but I'm ready for a new one that hits the marks. I just hope it's still closer to the proportions and aesthetic of most of the modern lines than the upcoming SS86 re-redo Seeker and Soundwave molds.