The Saturn really was a 2D machine with extra chips thrown into the box to compete with the PS1. From what I understand most hardware features that were built into the PS1 had to be emulated through software on the Sega Saturn, making it much harder to develop for, as well as making 3D quite a bit slower.
Very few developers also took advantage of both CPU's on the Saturn, though the few that did take advantage of the full hardware actually came up with some really impressive results. AM2, Lobotomy, Travelers Tales, Game Arts, Treasure (with Grandia) and some of Sega's other teams showed some pretty nice things on the Saturn.
Interesting fact: Nvidias first videocard, the NV1 was entirely based on the Sega Saturn and rendered games completely in quads. The first games that supported the NV1 were ports of
Saturn games. The NV1 even had a port for Sega Saturn controllers on it. Though outside of Sega, practically nobody supported the Nvidia NV1. The NV2 was actually being developed for Sega's Blackbelt (AKA the Dreamcast) console but never saw the light of day, it almost brought Nvidia to bankruptcy. Though they did bounce back with the NV3 (Rivia 128) which was a true polygon based GPU and supported OpenGL. It was the card that saved their company.