Tales From the Shadows Updated (SPOILERS ABOUND)

[Riastrad]

That depends on how much G'raha understood of the time-and-space mechanism personally and whether he can explain it to Cid (and whether both of them agree that it's a good idea to do so).

Obviously G'raha has a full understanding of any parts relying on the Crystal Tower and/or involving the spell to draw anyone he stumbles upon the WoL across the rift. But as for actually getting there, it's not clear if he would understand how to build such a thing from scratch or whether he simply knows how to drive it.

I also wouldn't be surprised if this world's Cid, on being told about it, goes "wait, I invented what? That could be abused terribly and I must have been seriously desperate to even contemplate it. Don't tell me how it works; I don't want to know."

(And then the knowledge that it's possible bugs him so much that he figures it out anyway.)

It was seemingly enough for Emet Selch to take him as compensation for our failure to contain the light of the First. I'm not saying your wrong, I in fact agree with your hypothetical conversation Cid and Graha would have on the matter, but I am saying we are not done with the knowledge. It's too convenient a plot element for the devs not to use in some fashion or another and that is the real issue with Graha surviving. I myself would abuse the crap out of it if I could. The worst part is, why wouldn't they use it to secure the future at a much earlier time like big heroes? Entire nations have experienced tragedy and loss at the hands of the Empire (the same Empire that created the weapon that sealed our fate and that of the world). Why not nip that problem in the bud instead of travelling to the first? And now that we are back on the Source, can you imagine the report our allies are going to get? "So we traveled to another reality and across time to save everyone! Oh, yeah time travel is possible! What? Use it to win the war? Why on Hydaelyn would we do that?"

Thus my love and hatred for time travel stories. The obvious never seems to just work without some contrivance to stop it from being so. Some will give all manner of reasons why it can't be done, all the while ignoring that time travel has been cracked along with reality jumping and seemingly works well enough to save not one but two worlds at the brink. The answer of why it wouldn't work doesn't make any sense if it would have been easier to do than what was already achieved.


tldr; time travel is apparently possible and it would have been easier to do than reality jumping and time travel combined.