Being too late for a party and ambition to become third dota and absolutely devastating anoncement that blizz ceo did. Even more I think anoncement did more damage than being too late for party.
I mean, I love game and still play it. Even after all these dramatic news, game still doing fine. Blizzard should have adapted their strategy and just continue to slowly develop game like Smite did. Same thing as starcraft 2. Even as there is no development in sc2, competitive scene is doing great, same as hots but even if blizz thought that hots is not worth it, there should have been gradually decrease in development, not like it happened. Pretty much it was early gg from blizz. Yet still game is alive, and I barely see queue over 1min. Qm and aram is like 10-30sec queue, rating is like 30-50.
I count hots as second moba killed for absolutely zero reason. First one is epic games Paragon that was sacrificed for sake of fortnite (even so it was right decision, but I can't say same for blizz).