Rad Racer had some great music! I think it is a classic example of an early racing game.
I am strongly partial to SaGa Frontier and SaGa Frontier 2. I normally dislike non-linear gameplay, but SaGa Frontier had a lot of unused content.
SaGa Frontier 2, on the other hand, still remains a beautiful game with only a bit of unused content, but I would love to take another look at the world or see some additional content about it.
Chrono Cross and Xenogears are games that would benefit from a remake of some kind, too. I wonder if Xenogears could be done as they would need to get the original writers to form a cohesive narrative.