Turning Tyrande into a villain (just like turning Jaina really) would be the most toxic storyline Blizzard ever wrote.
"Woman who lost everything -- her home, her friends, her people -- after devoting her entire life to helping others through sacrifice, is somehow treated as the villain who needs to be put down."
You can't write a more toxic storyline than that.
I'm sure Blizzard won't do that anyway. In the past, they were genuinely surprised that some people (probably Horde fanboys) thought Jaina was evil. Because in their minds, and in the mind of anyone sane really, Jaina was not evil. She was just traumatized after everything she lost, and had every right to seek vengeance.
Same thing here with Tyrande. She is 100% a victim, and does not deserve to be turned into a villain at all. For 10.000 years she has sacrificed herself to protect her people. She took within her flesh the almighty power of a god, which risks to tear her apart, so that her people could reclaim their home. She is at the bottom of the list of people who deserve to be killed off.
Plus who could even replace Tyrande? Malfurion and Shandris are useless, while Maiev is too much of a renegade to take up any leadership position.