1. We aren't talking about Shedinja. We are talking NINJASK. Very different. Shedinja doesn't even learn baton pass.I've seen Rock Slide and Stone Edge used so often in movesets I'm not really going to consider Shedinja, who automatically gets killed by them.
2. Even if i assume you are talking about Ninjask... there is something called "Protect" and "Focus Sash". With protect, you are guaranteed to pass at least 1 level of speed to your ally. With Focus Sash, you are nearly guaranteed to pass 2 levels of speed and a swords dance to your partner. Nearly because of T-Tar's sandstream which screws that plan up. With Protect + Substitute, you are pretty much guaranteed to pass upto 3 levels of speed down (Protect -> Substitute -> Protect).
Taunt and so forth screw with your plans, but hey, they screw any baton passer's plans anyway.