There's a lot of varieties of gush decks. But I think many of them would replace 1 of the gushes with a land. Many people cheat the mana base with gush a little bit knowing they can make up a land drop or use it to protect against waste/strip effects.
Outside of that I think in many decks people would take 2 ofs and 3 ofs and add another one one of them for better consistency. When you have as much draw as many blue decks use now (gush, ponder, preordain, brainstorm, ancestral, dig, treasure cruise) you can get away with a little less consistency. But if you remove some of that draw you either replace it directly with other draw or firm up the consistency you sacrificed in the first place. Part of gush's appeal is its efficiency and I'm just not sure there are other draw card that are as efficient to make them worthwhile. So fall back to more consistency.