I thought that was a great little scene.
It's the first time he's getting serious screen time, he's a legend the universe, and Rey (+audience) is expecting to find some revered and noble Jedi Master.
Instead she (and the audience) find a sad old man who is doing nothing but surviving and brooding.
Luke was also a farmboy too, so it's not out of character either :)
On the whole though, after a second viewing, I don't think the film is good.
Too much really stupid stuff (flying Leia, slow bombers, Holdo not saying the plan for no reason etc...) weaved in with a bit of a rubbish plot setup and too many shades of Empire.
The entire casino planet could have been cut and absolutely nothing would have been lost, all it needed was some quick 5 min hand waving to get Finn and Rose on Snoke's ship.
I'm also very surprised in the 10 months of editing since Carrie Fisher passed, they didn't cut the Luke dying scene out to allow Hamill to carry the torch a bit in Ep 9.