Tal Rasha's for Wizard is the easiest set dungeon, in my opinion.
Do not be surprised if you master it on the first time without even really trying. I personally did not know I had to kill the rockworms in order to master it, wasn't aware they actually counted for the 'kill all enemies' objective, as they were part of a separate, additional objective.
I had enough time to run from the very end of the set dungeon, after realizing i had 5 or 6 enemies left to kill... go back without using blink (walking, since I know blinking won't always let invisible/burrowed units 'aggro' you and appear to attack), and kill every rockworm after only half-remembering where they were and waiting for them to pop up. Took ~25 sec to find the very last one, still finished with enough time, mastering it on my first attempt.
Invoker Crusader is also ridiculously easy. Just get hit by stuff.