That says more about those reanimation targets than anything else. I'd rather pay 3 mana for Necromancy on Griselbrand and get 7 cards than pay double for Seasons Past to get ~4. I'd rather pay for that than for anything else in Cube, too. I wouldn't play that 8-mana draw spell because it doesn't affect the board (cf. Seasons Past), but I'd pay 8 mana for Cruel Ultimatum or Tooth and Nail or something.
I can buy the argument that Seasons Past is unique and more fun whereas Ever After has other cards like it, but 'Ever After is slow, Seasons Past isn't' is just untrue.
It's less that Season's Past isn't slow, and more that it's effect is more acceptable at a slower pace when compared to MTG's card library. It all depends on cube environments. If your cube doesn't have any real endgame reanimation targets and you're goal is jut to reanimate a couple of 4-5 drops for the win (like SOI limited was), then Ever After is a fine card.