Thunderclap (and thus Weakened Blows) is the most important as a tank, Shockwave, Dragon Roar, Stormbolt, Heroic Throw and Shattering Throw as far as i now also require no expertise to land.
Indeed, though for warriors all secondary stats are very close in value, that you shouldn't feel too bad because you're not hardcapped for expertise, It's certainly a goal to aim for., but not something you should really keep no matter what. Alot of the raid drops lack hit/expertise so maintaining your caps can be arduous, but but that doesn't mean you should stay in blues just to keep the cap.

