For the first time in years i think blizzard nailed it down with the character of Thalyssra and her whole storyline. The whole Suramar quest chains was painful to do at first yeah, but the story development of that whole arc is to me by far the most well crated and told storyline in WoW, with engaging characters and a true leader and rebel in Thalyssra.
I honestly think that all o this work would be such a waste if they dont continue her journey in the next expansion.
If you think about it we helped her so much to invade the Nighthold, maybe in the future she will give us back the favor and help us in our journey.
ame thing goes for other characters too often relegated to one expansion for no reason really.