You're right about the controller, but I don't know ... IMHO N64 is where they started to get less exciting as far as their internal hardware, but capabilities were getting more exciting overall.
The NES's CPU was a 6502 without decimal mode and certainly not exciting, but it's PPU wasn't too usual. 64 sprites, 56 colors, and a 2x2 screen virtual tilemap. I don't think any system had a big virtual tilemap quite like that at the time
SNES is definitely unique. Rotation and other transforms on a huge tilemap in hardware. No programmable sub-CPU or DSP is pushing pixels at all, you literally program 8 registers on the video chip to set the scaleX, scaleY and other parameters and the graphics chip outputs transformed pixels.
32x brought similar capability to the Genesis but it had some SH-1's performing transforms on textures I think, it was more similar to SuperFX than the SNES.
IIRC N64 was pretty much an upgraded PS1 polygon engine (hardware was SGI dervied like the PS1): one with a higher clock rate and a separate DSP for calculations instead of the GTE, but hamstrung by cramped cartridge ROM instead of a CD and really low texture cache.
After that Nintendo started using ATI for graphics hardware and adopted an IBM-designed PowerPC-arch CPU (as did Xbox 360) that lasted until the Will U.