I bet it is Ysera and not Merithra in cinematic.Green dragon has more deep green color and Merithra has more yelowish skin tone.Also there are 4 dragons flying to Alexstrasza and we see clearly only Nozdormu and Kalec. They may be Wrathion and Merithra, but we do not see Wrathion in cinematic. So I want to believe there are Ysera and Merithra.As we know Shadowlands citizens can travel to living world and Ysera is technically reborned (yeap, with problems). So in my opinion they are just hiding content of 9.2.5.If "the world is healing" we will finally remove the sword. And Ardenweald / Tyrande / Ysera story may end with a planting of new world tree.Or... May be I just wanna her back too much. :'-(