Hasn't Lucas done far more than JJ ever could to ruining the Star Wars brand.
I'll say no. Lucas created the brand. While the first three cannot absolve him from the second three, the former still greatly outweigh the latter. Lucas didn't do his legacy a favor with the Jar Jar's, the Youngling Slaughter, Hayden Christensen, etc. But he did found the brand.
Yesterday, May the 4th, is now an acceptable holiday amongst geeks. That's rather telling of the passion and involvement of the typical Star Wars fanboy. I'm glad Lucas is done with the series, no doubt, but I think an Abrams miss could end the franchise entirely with the wrong movie. Who'd want to touch it after a new disaster? Star Wars would drop into B movie status. Spider-Man and Batman have been able to survive because their stories get retold. We can't get shocked again about the wisdom of Obi-wan, the lineage of Luke and Leia or the betrayal of Lando. A reboot would be disastrous.
If Star Wars is to survive, it will be with an expanded universe. IMHO, the only way it keeps expanding is with a compelling new tale. I'm not sure Abrams is as up to the task as maybe a Peter Jackson or Christopher Nolan might be. Those guys can tell a story. Abrams' stories, from my experience, are shallow and gimmicky. I fear it will be a two hour battle with flashy effects, a chase, and some sort of surface love story.
I don't think Abrams has the skills to further the universe or expand the story and it could grind the once mighty franchise into the ground. I hope I'm wrong...