Blink Strikes?...
If your pet has to sit on a boss for some reason (such as on that Gunship fight in Dragon Soul) then yeah, you wouldn't use that. You would, however, keep your pet on passive. And if you're BM and your pet can be on your target but isn't, it will die exponentially slower.
I'd assume he'd figure out how to micromanage pets by the time he hits 90, though. :P Overall, having /petattack bound to a common attack is pretty good advice and makes micromanagement easier.