I judge all 3 systems by the USA and Japanese release element. But if you really require me to trash the Super Famicom Nintendo of Japan side of things I will,as I can just as easily name off crap that sucked for that system. Ashita No Joe,Violinist Of Hamlin,Libble Rabble,Sonic Wings,Snoopy Concert,Hiryu No Ken S,Hokuto No Ken 6, the complete shit ports of Art of Fighting 2,Sengoku,Final Fight 1 ect ect... I could go on and on,but Im not because its a complete waste of my time. The fanboy thing doesnt apply to me.
There are tons of Snes games I love to death,like Dracula X,Contra 3,S. Castlevania 4,Super Ghouls and Ghost,Chrono Trigger,Pilot Wings,Super Mario World,Super Mario RPG,ect ect.. but I stand firm at the Quality control comment,because there really wasnt any. What you mettioned really boiled down to minor bug fixes,NOT making the game fun,not really game quality improvement. I only know of a few titles that Nintendo actually set aside and requested the game company to improve,and only because they were banking on those titles to be killer aps in the battle against Sega.
I perfer the Pc Engine the most because of the arcade ports and shooters. I mostly play arcade games,so my loyalities lay with that system. As for original content,I feel all 3 systems had enough of it to keep anyone happy if they play both domestic and imports.