I agree, for me RRT4 is one of these game bringing innovations inside a certain genre.
Speaking about the racing gameplay, I must say I didn't really enjoyed it this much back at the time. Honestly, I'm playing and enjoying this game due to all the global artistic creation (graphical/musical) created around it. The typo art, the black/orange color scheme, the implementation of visual novel aspects (Sophie Chevalier <3), the fabulous cut-scenes showing new cars coming on your showroom, the gorgeous soundtrack... I never felt this classy atmosphere again. RRT4 is a piece of art, a artistic and innovative interpretation of a dreamed racing world.
This game is representing a golden age in term of artistic development on PS1, going closer of other nostalgic PS1 creations I also have in head like
this game or
this menu.
A complete remake of RRT4 taking note of these elements would be... This would be my Shenmue 3 I think.