well i did not say that Wu would most definatly die... but here is a little something to remember with the "Time Blades"
and given that the blade that Acronix(?) was using... It would be possible that the blade possibly speed up Wu's age until he possibly becomes too weak to talk, you know, reaching that time of age were you will not even be able to walk, even breath properly.
by the way, im not sure which one of the "Time Twins" the one in the trailer is, so im just assuming that its Acronix, based on that he wears his green cape on the left side unlike Krux who wears his cape on the right side. Plus while i could not get a good look at the torso, it does not look like the "Time Twin" had an iphone or anything on him.