The whole point of Dismember being good is the fact that you don't need a single Black source in your deck for it to be good. So, if someone down the line gets the Ball and cut Black, you don't care, because you p1p1'ed a colorless card. In fact, that's the goal in a MM15 draft: You stay as open as possible in the first 4 picks in preparation for picks 5 to 8, because those are the most important picks of the draft. You see what's open on those and pick an archetype (if nothing is open, you pick all the fixing and draft 5 colors).
Myrsmith is fine, but not amazing. You don't want to start your artifacts deck with a card that's not an artifact. It's more a reward for being in the archetype then an incentive to jump into it, like
Dispatch. Incentives are things like
Glint Hawk Idol or
Cranial Plating. Every archetype has incentive and reward cards. The key is indentifying which is which, so you can read the right signals.