well Jackie Chan and New Adventure Island are pretty awesome platformers but you are right that it never had that one big blockbuster like Super Mario Bros or Sonic that would make people buy the system just for that title.
I already had the system, and I still didn't buy those games. The only reason why I had Bonk 1&2 was because they were pack-ins. I didn't get Bonk 3 until last year. There isn't really a shortage, per say, of platformers on PCE, there's just a shortage of anything better than a C+. Maybe Mario and Sonic are asking for too much, but what about Rystar, Rocket Knight, Heady, etc? Shit even Vector Man embarrasses most PCE platformers, most of which seem to be Wataru or Wonderboy hacks. Same floaty jumping arc, same shitty shops.
I'd say the biggest missed opportunity on the PCE was the fact that the last few years of the system were dominated almost entirely my menu driven games. Galget, RPGs, and Digital Comics, mainly. At the end we all had CD systems and Arcade Cards but if you wanted a shooter, a platformer, a beat-em-up, or even a sports game you had to go to the early CD or even HuCard era for any kind of selection. Of course, before eBay, this forum, etc it was really f*cking hard to find PCE games that weren't brand new so...there wasn't a lot of "action" in 1993, 94, 95.
Specifically, I guess I would have liked to see an Assault Suits series game for SCD. Given NCS Masiya's huge support of PCE its kind of odd there never was one.