It sounds like I'm hearing a theme in this thread that many of us didn't see the Luke we wanted to see, but I guess I have a bit of a contrarian view.
I feel Luke's story was true to what I see as the purest Star Wars canon: ie the original trilogy. If you wanted to see the epic lightsaber battle, then you're asking for Yoda versus Count Dooku in Attack of the clones. That was fun in the moment, but a bit ridiculous in hindsight.
Instead, we have a nice parallel with the original trilogy, which was the most powerful Jedi living in seclusion on a lost planet. He reluctantly trains Rey (a bit accelerated, but whatever), then Rey leaves in a huff to go save the world. Much like Empire Strikes Back/Return of the Jedi where Yoda is no longer in the world, Luke has a massive influence on Rey's path from his little island, then we see a twist in which he influences events across the galaxy, showing a power we could not have imagined.
Sure, he could have come flying back to the rescue like Yoda in attack of the Clones, but that would have been disingenuous and pretty cheap; and most important to me, it would have felt like the prequels rather than the original Star Wars.
I'm sorry that the movie didn't play out to every ridiculous fantasy we could have imagined, but I think it would have been a cheap thrill, out of sync with what we love about Star Wars (unless you love the prequels, then more power to you). I think what we got feels more like the Star Wars of my youth, and I believe it will stand up better over time.
... but I could have done without the flying Leia.