I personally would not recommend using a macro for defensive cooldowns.

But anyways, I'll say that most tank busters are going to require a cooldown+the tank's special mitigation. Most tank busters can be dealt with a rampart+TBN/sheltron, or in the case of warrior, rampart+whatever becuase you've got a ton of options. As for cleaves, one minor cooldown should suffice.

Certain cooldowns can deal with most tank busters just fine, alone. Shadow wall, sentinel, and vengeance. If it's a little dicey, double weaving reprisal will make the damage comfortable to take. Still, the best advice is to go out there and experience the fights for yourself. They're all timed and scripted, so tank busters occur at the same time, every time. At that point you should try using your cooldown a bit before the tank buster actually occurs so you can mitigate the auto attacks that come before and after. Do keep in mind this requires a lot of time to achieve, but it's something to look forward to.