I personally wish dark archons saw more play, besides just stunning mutas. Their feedback is great, very cost efficient vs defilers and HTs.
And arbiters in PvZ, since zerg often builds highly fortified bases but never expects arbiter, whose recall could bypass and wipe out main with all tech (costly in terms of time and resources lost, even if everything gets rebuild immediately).
And mech in TvZ. A pity that queens play have become so efficient that it seems there is no good counter to them.
