Quote Originally Posted by Dwill View Post
Breaking Vines in T6 and Cursed Shriek in T7 are examples.
Not to nit pick, but those aren't good examples.
Breaking vines takes like half a second with Sprint, and Dots don't typically need a refresh during them.

Shriek is an 8 second counter, so plenty of time to refresh dots if required before moving into position.

I don't think there's actually any scripted or random parts of a fight that effects Summoner and would require faster casting.