Re: the TIMELINE thread
In the SDCC clip that leaked online, they don't say the time travel is to stop Sentinels but to give Xavier a new sense of hope. That sounds a bit vague, so there may be more to the conversation that we haven't yet heard.
They must have a specific reason for choosing 1973. There must also be a reason that they choose Wolverine.
The time travel must also surely be a one-shot deal or they could use it to alter other stuff like Cyclops' death, or the development of the cure, or Jean's death at Alkali Lake, or Xavier putting the block in Jean's mind.