Why did R2-D2 wake up so conveniently?

There are quite a few happy coincidences in Star Wars: The Force Awakens. This must be the happiest one – R2-D2 wakes up exactly when needed, in order to wrap up the film. What made him wake up?

Did Luke become so powerful that he used the Force in order to wake him up from the other side of the galaxy? Or was R2-D2 programmed to wake up when Rey arrives? No, it is neither of these.

According to J. J. Abrams, “BB-8 comes up and says something to him, which is basically, ‘I’ve got this piece of a map, do you happen to have the rest?’ The idea was, R2 who has been all over the galaxy, is still in his coma, but he hears this. And it triggers something that would ultimately wake him up. While it may seem, you know, completely lucky and an easy way out, at that point in the movie, when you’ve lost a person, desperately, and somebody you hopefully care about is unconscious, you want someone to return.” (via Entertainment Weekly)

Really, J. J. – it’s all about getting lucky?