Not saying they're bad, but they clearly didn't put as much effort into the Blu-rays as they could have.
eg using the same 2004 masters for the Original Trilogy, & all the hype about fixing all of the complaints fans had.
Lucas film made such a big fuss about having gone back & fixed all of the Lightsabers etc & produced screenshots of the fixed effects...turned out those shots were the ONLY lightsaber shots they fixed, & they'd left all the other messed up lightsabers unfixed
I think Cameron is probably more the type to put that extra bit of effort into his films (as evidenced with the great transfer of Aliens) than Lucasfilm who never seem to be bothered- just good enough, is good enough for them