ST The Characterization of Luke in TFA

I only saw the movie for the first time yesterday so apologies if this has been discussed already (I've tried to avoid spoilers until I saw the film myself).
Overall, I enjoyed the film immensely and am looking forward to see where the story is taken in episodes VII and IX. The one area which bugged me was more to do with what we didn't see between eps. VI and VII, namely the fall of Kylo Ren and Luke disappearing.
We're told that Luke vanished (and has been gone for numerous years, based on comments from Han and Leia) following the fall of his nephew, Ben Solo to the dark side during his training as a jedi. Although we don't see what Luke did to try and 'save' Ben, does anyone else not feel that Luke simply isolating himself after the fact is not only very irresponsible but outside of the characterization of Luke we saw in the OT?
Luke's character in the OT is as follows:
ANH - Having no real prior allegiance to the rebellion, pushes Han into saving Leia on board the death star and then joins the battle against the Death Star as a pilot in the front lines
ESB - Due to his loyalty to his friends, Luke flies off to save them despite Yoda's warning he is not ready.
ROTJ - Luke turns himself in to Vader as he feels he is jeopardizing the misson of his fellow rebels.
For me, this shows Luke as a principled and loyal person which seems to be somewhat undermined by his apparent disappearance before episode VII; after all, Luke is the sole remaining Jedi and knows first hand the power of the Sith and the damage they can cause on a galactic scale if left unchecked. Instead of being like 'oh, crap, things have gone to ****. well, peace out everyone!', I feel Luke would be trying to move heaven and earth to set things right, especially if it's a) family and b) he feels personally responsible.
If worst comes to worst, even killing Ren is better than going into hiding (unless he is outmatched a la Yoda and Obi Wan) as at least it will prevent the First Order from gaining a feared and powerful figurehead. As for being outmatched, Luke should have been able to beat Ren easily given that the raw Rey seems to be at least his equal in terms of force strength (bowcaster wound aside, she prevents his mind control earlier in the film).
Also I appreciate that the first order are trying to hunt Luke down but is it really necessary for the most powerful being in the galaxy to run away to save himself? Is he really at risk at the secret resistance base, surrounded by allies, than he is in isolation?
Of course, Luke's side of the story may well be explained in later episodes but it's something that didn't quite sit right for me in an otherwise excellent film.
I'm keen to see how others interpreted this plot point and understand if there's a reason I've missed.


Mav Edit: As pointed out below, there is a Luke thread. Locking.

 

Hi. Welcome. Glad you saw TFA.

There's a super huge Luke thread just a few steps down. You should post this there. Everyone is discussing Luke. There's a pretty bloody fight going on. Lots of sweaing. Blood on the carpets. Lives ended. Cats and Dogs, living together. Mass hysteria.

Nah...it's actually quite cool. Chill. Sane (for the most. Wait...who I am kidding. It's pretty insane)

 

Will do, thanks