The scene with Luke is at the same time the logical conclusion to TFA: “Luke has vanished” now we found him, AND it is also a “cliffhanger” in the way that the audience does not know how Luke will react to Rey giving him the lightsaber.

Everyone assume that he will train Rey, but she just comes to give him the lightsaber and maybe ask him for help.
So, we have one character that is not really asking to be trained, IMO (and who does not even seem to be in need to be trained anyway! Maybe just to control her power better), and a character who have good reasons to not train anyone anymore…