Click HERE to see this thread with all of the graphics, features, and links.

Did he ever reach his full potential in power with the force, or was he never able to because of the dark side?

I believe he could've been far more powerful than he was at the time of his death. Two things limited him: 1) I've heard the loss of his limbs reduced his overall force power - this is probably EU since it's not actually mentioned in the movies other than "he's more machine now.." 2) I believe the Emperor limited Anakin's growth in the powers of the force. Sidius wouldn't want his apprentice to kill him as he did his master, Plagueis (canon- mentioned in RoTS), so he would keep Vader's knowledge of the Force suppressed.

Hopefully, with the new TV show focused on the timeline between RoTS and ANH, we will see more of how powerful Vader really was after the whole limbs cut off thing. Other than force choking helpless peons around him and dueling with either an old man or a young, untrained kid, we didn't see Vader really flexing his Force knowledge in the OT.

He never did because he got his limbs cut off and body ruined.

If Anakin had managed to kill Obi Wan on Mustafar, he would reach his potential...But we know how that ended