Filming Begins, Director Joins Twitter

You do know why Abrams is greatful to Rian Johnson, don't you? Because Rian Johnson took the heat over ruining Luke's character and killing all of those storylines. Had Abrams made episode VIII he would've killed off most of the same storylines Johnson did. The original writer of TFA (Michael Arndt) couldn't bring himself to write Luke in a way that was defamatory to the character (as Kathleen Kennedy likely wanted). And he couldn't write the character in an integral way that made him seem completely insignificant. So his answer was to keep scaling back Luke's role in TFA with each rewrite. By the time Abrams got the script he didn't want any part of writing Luke's character. He likely foresaw the backlash and shoved him into a dialogue free cameo (which seemed like a brilliant opening to the character in the next movie at the time, despite some fans disappointment). It really amounted to Jar Jar Abrams shirking the responsibility of what they intended to do with Luke's character all along.