The SNES wasn't quite as weak as we've been led to believe, and the SA-1 was eventually available (and it was probably quite a bit more powerful with that), but yeah. And it was a golden age, a real burst of creativity that the new hardware enabled.
I think of the Sonic and Donkey Kong Country series as the exemplars of their respective console's designs. Both are platform games, the most fashionable genre of the time. DKC shows off every graphical trick that the SNES could pull off (OK, no Mode 7, but there's colour blending, HDMA tricks aplenty) and has a fantastic synth soundtrack. Sonic shows off the Mega Drive's faster processor, and has an equally fantastic FM soundtrack. Also the Mega Drive's higher resolution is quite important to Sonic. Neither use helper chips. If you want to say what stock hardware can do they're pretty good, and they're completely different as they play to their respective hardware's strengths.
I guess Super Mario Bros would be the NES equivalent for that, it uses no mappers and was intended to be the ultimate cartridge Famicom game at the time.