Quote from BadPlayer6 »
2) FoN crowded out other MR items. Riot balances according to the abuse case. As long as FoN existed, Riot couldn't make another medium-high MR item, since FoN + other item would've just been way too much MR, and would've countered mages too heavily. And as a result of that, there wasn't any variety in choice for lategame MR. So by removing FoN, Riot opened up the way for more medium-high MR items, which would allow for a greater variety in choice when buying MR.
This guy's got it. They basically opted for runic bulwark and other MR items and not FoN.