They can be solved fairly easily, and, unless combined with the other half of their combos (proliferation of counters, Mycosynth Lattice, Wheel of Fortune), dont have a huge impact on the game for more than a couple of turns
So that includes other utility lands, utility artifacts like Chalice of the Void and Tormod's Crypt, X-cost spells like Endless One, 0-cost spells like Pact of Negation, and even no-mana suspend spells like Glimpse of Tomorrow
As we know, doubling anything can get you ahead fairly quickly
Evolution to work around an item lock and keep up with the opponent
All four decks are powerful in their own way, but Scions & Spellcraft has the lowest impact potential