Also, that would be a cool idea for your edit! They fail their mission, but if Rey has “seen” where Luke is, it would also help justify why Rey off all people has to find him.
That’s the biggest benefit alongside R2’s convenient awakening, but the reason I thought of that was to fix the deeper issue of Luke’s exile. In TFA there was some confusion as to whether or not Luke wanted to be found or had a backup plan in case people needed him, but in TLJ he seems genuinely surprised that anyone could find him and is pretty clear that he came to the island for good. R2 having the final piece of map to his location makes no sense in this context, especially since we know Luke didn’t take R2 along as his X-wing is at the bottom of the sea.
So now Rey is given a vision of the map, and I’m planning on taking out any reference to the Empire/R2 having the rest. It just makes no sense that in 30+ years nobody in the Republic would stumble across these Imperial maps and R2 would just download them from the Death Star and then forget he had them. I think it’s much more interesting and realistic to have a religious ascetic piece together a bit of star-chartery that’s practically worthless so that their situation is truly hopeless without Rey.