Very interesting question. Here is my take.
Many consoles have succeded and failed, regardless of power and capabilities. Though most which succeeded were less capable, many had features that made them stand above the rest while staying at a low pricepoint. From my point of view, what matters most in all generations is the ability for the console to provide games.
Due to the difficulty to develop games for the saturn, and the awefully expensive pricepoint of certain fundamental accessories (memory add-ons), the system was lacking games. But, if it were simply close to the genesis as the Neptune would have been, it would be competing with the Super NES and low-graphics games pumped out on the PS (FF remakes, tactics, 2D games like Megaman X), and if the Genesis couldn't beat the SNES the Neptune would not have done much better without some kind of graphical leap which the Saturn offered.
Ultimately, Sega did right with the Saturn, and they had the devs to make a great console, but the system itself needed to be easy to write code for, and needed to support cheap peripherals like memory sticks.