SPECULATION Has Luke lost his powers?

A lot of exposition here guys, so bare with me.

In the Aftermath novel, Tashu (sp?), a former servant of Palpatine explains to Wedge that the Sith could drain the powers of others to strengthen themselves and prolong their lives.

Now, we know that Snoke is a) disfigured, scarred and probably a zombie lookalike, b) a Dark Sider and c) vulnerable.

We are also reliably informed that Luke Skywalker is missing and the forces of good and evil are looking for him. We have long questioned why Luke is missing, why he isn't helping his friends etc.

What if Snoke, whoever he is (I say Plagueis) has either absorbed Luke's powers or has sought to do so? Snoke's vulnerability could be that he is gravely injured and has survived by absorbing the Force powers of others. Maybe this is why he has sought the artifacts (lightsaber, mask etc) - they could contain some Force energy (as established in the Shattered Empire comics). Or what if he has been living off of Luke's energy? (A bit like Skelator does I think in Masters of the Universe to the Princess).

Perhaps Luke is stranded, in captivity and being abused by Snoke in this way? Or perhaps Luke managed to get away but has been unable to help his friends because of his loss of powers? Maybe he remains in exile because he knows he is weak but must survive to pass on what he has learned?

One must question why we need a new hero (Rey) to banish the evil in the universe. We have Luke Skywalker. Yes, Kenobi and Yoda were both powerful in the old trilogy and they needed Luke. However, I think those films really suggest their time was up for a number of reasons. Luke is the son of the chosen one. In TFA he will be slightly older than the Darth Vader of the OT. He must surely be very powerful? So why do we need Rey? I'm thinking that it could be that Luke has lost his powers and that is why we need Rey. Luke can still train her in the ways of the Jedi of course but there is very little he can do himself.

It's highly speculative I know but let's hear your thoughts!