So im assuming everyone has seen the future dragonblight pic showing deathwing dead on Wyrmrest Temple... Now as for how he dies I think I have figured it out...
A) Galakrond ressurected by an old god which would explain the giant hole where his bones used to be in one of the pictures they posted and the tentacle in it... This would also explain how Deathwing got speared on Wyrmrest Temple.
B) Deathwing was flapping along in the dragonblight getting ready to attack the tower whennnnn..... BAM!!! He gets nailed with a giant plasma beam coming down from the sky Grafton style from Halo Reach!!!! It would seem that Rhonin finally decided to put his 24mil mana to use...
Would love to link the video from Tip of the Spear but can't...