Is EXE1 really that legendary? I haven't been around during the time the MMBN series started so I don't know how much it got hyped.
I don't remember how I found out about it. Probably either Planet Megaman or GameFAQs.
But yes, BN1 started the whole series, and for Capcom, it's legendary in terms of being a source of easy remake revenue since Starforce (more or less) flopped. Of course, BN6 was where SF1-3 are in terms of marketing awareness.
Either way, BN1 had a fully-connected internet (16 non-distinguishable areas), 15 chips to choose from instead of 10, the rough draft for the Program Advance system, had a lot of the most favored and future-repeated NetNavis in the same game, etc.
Personally, I think they just want to say ALL YOUR BASE ARE BELONG TO US again, but that's just me.