This is a difficult question, arguably without Mario the entire video game industry would not look anything like it does today. Super Mario Bros. is what made the NES popular, the NES in turn is what revitalized the video game industry - without that things likely would have unfolded very differently.
That being said yes I would still be a fan on Nintendo if, all other things being unaffected, Mario didn't exist. Zelda, Pokemon, Fire Emblem, Kirby, Donkey Kong, Pikmin, Wii Sports/Fit/Play, Advance Wars, Metroid, Animal Crossing, etc. hell any one of those franchises is enough in my opinion to warrant my being a fan of Nintendo.
Systems Currently Playing: WiiU, PS3, 3DS
Also Have: Atari 2600, NES, SNES, PS1, N64, PS2, Wii, GB, GBC, GBA, DSLite, DSi, Android (RazorMax), iPhone (4), iPad (2)
