Hayden publicly said his wooden acting was at the direction of George Lucas.
While I would never call him a particularly "gifted" actor, he has shown in other work that he can be solid. Case in point, "Shattered Glass". I thought he did a fine job in that one.
My personal opinion has already been shared by some--no one had the courage to tell Lucas where things weren't working. I also believe a similar situation occurred with the planning of "Indiana Jones and the Kingdom of Crystal Skull" (in the early 90's, Lucas had planned on the 4th film in the Indy series being titled "Indiana Jones and the Saucermen from Mars", ultimately, around the time Independence Day was out, Spielberg--while not being enthralled with aliens in an Indy movie--was able to sort of kibosh it since it would have been viewed as "too similar"...now, I believe Spielberg should have done the same with Crystal Skull, but that's another debate for another time).
Speaking of Lucas, if anyone watched his recent interview with Charlie Rose, it seems quite apparent that he's not a fan of TFA, and perhaps he is a bit sour that Disney didn't want to go with his story ideas for this new trilogy (he even appears to call Disney "white slave traders" before failing to complete his thought/sentence in which he calls them that). Oh well, George. You sold you company and the rights to Star Wars for 4 BILLION dollars, you showed with the prequel trilogy that you may have been out of touch with not just what the audience wants, but with storytelling in general.
I also think Lucas was seduced by CGI and thought it could help him overcome some of his limitations that led to him handing off directing duties to collaborators for the OT sequels. He clearly focused his creative energy there at the expense of script and acting.
I wish Lucas had stuck to the Empire blueprint for the prequels and I wish he was doing the same for the new trilogy. For everything that I enjoyed about TFA, it still feels too much like fan fiction. Hopefully the next one can take the sequel trilogy in a new direction.
I don't have a problem with him liking CGI so much, especially in a world like he created with Star Wars. The simple truth is that the digitalization of movies (CGI, etc.) allowed him an opportunity to finally have a chance to show what had been in his head. The Original Trilogy, given the technology available at the time, just never had that chance. He touched on this a bit in the Charlie Rose interview, talking about CGI allowing him to do a Yoda fight because he always wanted to do/see one.
Also, he has absolutely 0 to do with The Force Awakens. He's not involved at all (your last part there, seemed to indicate that you believed he had something to do with it, perhaps I misread it?)