Great concept, especially the talents (a lot of originality there!)

The basic ability with the highest CD is Dimensional Shift (Tassadar) at 20 seconds, followed by Tyrande's Sentinel (18 sec) and Anub'arak's Burrow Charge (16 sec). Furthermore, plenty of basic abilities have 15 second cooldowns (Blizzard; Lightning Rod; Gazlowe Turrets; Pufferfish; Nova Decoys; Earthbind Totem; Overkill) and even more have 14 sec and 13 sec.

Thanks for the feedback! @LainEdel: While I understand your concern, it seems to me that hitting the sweet spot between non-viable and OP that you raise is simply a matter of tweaking damage numbers (which I have purposely left out here in the design). Note that channeled abilities like Mind Flay have some crucial drawbacks: (1) they deal their damage over time instead of right away like most Basic Abilities; (2) they render the hero effectively immobilized for the duration of the cast;...

Thanks for the feedback! I think the health and mana regen aspects of Vampiric Touch, Shadowform, and Vampiric Embrace (which I rolled into Shadowform, see explanation above) were the key mechanics that I wanted to bring into HotS with this character, and I think Mind Flay and Psychic Scream are pretty iconic abilities. I did 'make up' a new ability with Vengeance of the Loa; it mutated from Mind Sear when I realized that I should highlight the Witch Doctor aspect of the character. Perhaps I...