It is because he comes back in Legacy of the Void. With a name like ‘Fenix’ (phoenix), it would be easy for him to come back… somehow. Once his character is established in Legacy of the Void, then, and only then, will he emerge in HOTS. Putting him out there now would be a huge LOTV spoiler.
I imagine the same is true with Artanis and the other heroes. Artanis will likely be given away for free if you pre-order LOTV.
One thing that many people, erroneously, do is to divide Heroes of the Storm through Warcraft/Starcraft/Diablo/Other themes. World of Warcraft is NOT warcraft. It is WoW. Warcraft is this…
If you’ve noticed, Blizzard is not putting in WoW heroes so much as Warcraft heroes. Look at Jaina. She is exactly like the Warcraft 3 version of Jaina. Uther is Warcraft 3 and plays no part in WoW. Kael-thas and Illidan are Warcraft 3 heroes. Muradin is totally Warcraft 3 (even though they retconned him back into WoW). Sylvanas using poison arrows is totally Warcraft 3 from when she poisoned Arthas.
I think a better predictor of future heroes will be to look at Warcraft 3’s roster instead of World of Warcraft. I expect to see the Blademaster, Pit Lord, and Sea Witch soon.
One very interesting thing about HOTS is how Blizzard is prioritizing Warcraft 3’s universe over WoW’s universe. Tell me, what type of WoW heroes are in the game? Rehgar? Maybe Falstad and Stiches? I’ll give you Lili.
But only one true hero is from World of Warcraft.
Murlocs were never a thing until WoW, But we had Pandas in Warcraft 3. The dirty secret about WoW is that all the cool WoW content came from Warcraft 3. It’s no mistake that every “Warcraft” hero either has a strong tie to Warcraft 3’s heroes or actually is a Warcraft 3 hero.