I find Hallazeal annoyingly difficult to use. Turn 7-8 is so late in the game for a good single turn combo with him, and that's assuming you aren't overloaded.
I guess throwing him down turn 5 against aggro either sets a single turn clock or forces them to treat it like a taunt, but unfortunately single turn lethal on turn 6 is usually pretty easy for them if you ignore their board turn 5.
Crusher/Nzoth shaman are really hard to play and you need to stick to it for many games before it clicks with you. Managing overload and knowing when to drop certain combo cards is a major key.