Orglove, be careful because you're walking a thin line logically. Sure, Graboids have heinous speed -- but they're fragile unless you Burrow them at which point they're not fast anymore.
But more importantly, you can only have 6 Graboids in a deck. You have a choice then, in going for more speed (though many people wouldn't consider Shrieker on it's own to be terribly fast at 8
for 8 damage) OR some control (usually EQ+Rewind.) The control version isn't actually that fast -- it relies on slowing your deck down to give itself a chance, and if you can work around that slowdown (Pillarless decks, untargetable creatures, super-cheap creatures) it loses.
The speed version has the Burrow/unBurrow problem mentioned earlier where it's basically as fragile as a Fire deck but with less ability to spike (no direct damage, slower quanta gain) OR it's as slow as an Aether deck but with a turn of vulnerability before the creatures settle in to whittle you down. There's a little power in that flexibility, but it's paid for by a Mark that's basically sitting there useless for 70% of the game.
Summary: Don't credit any single deck with being able to do everything that the element it's based on can do.