There is (at least in theory) supposed to be a drawback to playing multiple colors by limiting the consistency of your access to the different types of mana, which you have to address by filling more of your deck with fixing
Jetmir, Nexus of Revels This fat cat (complimentary) encourages you to go wide with pride
Flying Dion, Bahamut's Dominant // Bahamut, Warden of Light Rarity: Rare TYPE: Legendary Creature // Legendary Enchantment Creature SUBTYPE: Human Noble Knight // Saga Dragon CMC: 4 Mana cost: USD: $21.57 EUR: 13.86 TIX: 0.00 EDHREC RANK: 4404 (3/3) Dragonfire Dive During your turn, Dion and other Knights you control have flying
That said, with the right commander at the helm, its still very much doable
6 Silverquill Statement A Savvy Investment The Silverquill Statement deck is the antithesis of raw power
These decks can be solid, but I dont see nearly enough Dark Confidants out of opposing Dimir decks