I have to assume if more people got to play Over-Extended and it had GPs or PTs dedicated to it that the ban list would be much larger.
I don't think so to be honest. Overextended decks were extremely close to Legacy decks in term of how they worked, but without wastes, duals, FoWs and whatever.
You had basically a lot of Legacy lists but with some crucial key cards absent or replaced. You had Elves! without cradles, 12Post without forces, Reanimator lists that used life/death and Goryo's Vengeance as their reanimation spells, Zoo which were basically legacy lists but with shocks etc...
I think That format would've been incredibly good and it showed what an eternal format with a good balance between spells and creatures is, but without the blue bias and absurd financial limitations of Legacy. The absence of FoW was compensated by the existance of MM as a safety valve and the absence of Petals, LEDs and Dark ritual which made storm combo and shit like Belcher/Oops just worse than elves!
Sure after things like Griselbrand, TC, TNN, Delver and others, they would've had to ban more cards.
Modern banlist philosophy is completely distant from my own vision of what a good format should be, banning reactive cards like MM in a virgin format is so shortsighted.
You remove a safety valve on the unlikely premise that it would be omnipresent? In a midrange based format? And with fetches+ shocks manabases , to boot. Like really, who thought MM could even be near the presence it had in legacy? And their justification of it "it was banned in legacy so it's obviously broken" no you fuckwit, it's a reactive card, it was banned because everything in legacy cost 1 but that wouldn't be the case in a format without BS, Force and Wastes compressing mana curves. Bah whatever i'm just ranting because i dislike everything this game has become, and even legacy is basically left to itself to become Vintage 2.0