For 3RR, you can destroy an artifact or a land, but that's asking an awful lot
Once you hit the mid- to late-game, Cleanup crew acts as a potent threat and strong removal spell, and cards such as Darling and Take to the Streets have anthem effects that buff your entire team, allowing you to swing for lethal damage
Perhaps alongside Leyline of the Guildpact, it might unlock the potential to splash an additional color as well
== CUT == Here are some cards I recommend cutting: Aeronaut's Wings, Colossus Hammer, Greatsword of Tyr, Inquisitorial Rosette, Mardu Monument, Team Pennant, Amazing Alliance, Cartouche of Solidarity, Rally the Ranks, Shared Triumph, War Effort - Most of these provide modest buffs or require too much mana to use in one go
Cards To Replace Impact Tremors is gone
This is one that I see having a bigger impact in 60 card formats