He also seems to indicate that THOR will be evolving or being "reinvented" again in these Avengers movies
Well, that kind of indicates that THOR isn't dying but then again death is IRRELEVANT when the Infinity Gauntlet is involved.
Also the Gauntlet could easily warp time and reality to restore a YOUNG Odin (Hopkins has indicated he doesn't want to play the part again), Asgard and all that perished in THOR 2 and 3, and keep Hela and Surtur dead thus negating Ragnarok.
However if that does not occur, I could still see THOR being a guardian of one of the infinity stones after the war. The space gem could be used to transport his people to a new Asgard, the Reality Gem could RESTORE Asgard, so could the Time Gem, but I suspect if THOR does guard or wield a gem it will be the POWER Gem. imagine his vast power as the GOD OF THUNDER augmented by the power gem!
Wonder what that means exactly? I liked some of the changes from Ragnarok.