When players talk about a 'spellslinger' commander, they're usually referring to a legendary creature that gives you a payoff for casting instants and sorceries, or sometimes noncreature spells in general
Even if you only cast one of them, theyll make for a great creature without truly needing the other one all that badly
Conveniently, Walls not only buy us time to get our game plan going, but several of them will ramp us there sooner
While most Eldrazi are colorless, there are Eldrazi in White, Blue, Black, Red, and Green with some instances of Devoid a static ability that makes a card colorless, no matter if it has colored mana as its casting cost
The only reason it is not a slam dunk S is that the enablers in modern are much worse than in Legacy