Luke having a small roll really bums me out.
But it's all setup for him to have a sizable, if not full on lead role in Episode 8. The ending shot looks to be Rey (Daisy Ridley) discovering Luke where he has been in hiding and boom credits roll.
Essentially Han in this movie is what Obi-Wan was for A New Hope. And Luke is the Yoda of this trilogy it looks like.
They are playing a long game here. Not trying to throw everything into just one movie. Got to keep the momentum rolling. Episode 8 is only a year and half away after The Force Awakens.
It's not like this is our one and only time we get to see Luke. The spoilers point to this being a cliff-hanger/setup for his full on return in Episode 8.