The Blu-ray changes are mostly subtle compared to the DVD changes. Off the top of my head:

Obi-Wan has a new (and ridiculous) shout to scare off the sand people.
R2 hides from the sand people behind a new CGI rock. How he got behind it is anyone’s guess.
Han and Greedo shoot at or nearly exactly the same time now. (Easily the best change, though it also makes you wonder why Greedo still shoots at all because George’s initial “reasoning” that Han was only shooting in response to Greedo’s shot is out the window, cause if they shoot at the same time that means Han would have shot regardless of whether Greedo shot.)
The door to Jabba’s palace has been digitally expanded to appear more imposing, but also looks odd and distorted and doesn’t really fit with the interior shots.
Sebulba is now digitally inserted into Jabba’s palace to further piss off prequel haters.
The Ewoks now blink, which somehow looks much creepier than the still eyelids they had before.
Vader screams “NOOOOOO” twice while killing the Emperor in George’s biggest “fuck you” yet to his fans. This was obviously done solely out of spite due to the fact that people mocked the “NOOOOO” in ROTS, which is probably the same reason Greedo still shoots and Jar Jar is in the ending celebration.

Those are the ones you’re most likely to notice. I’m not sure if anything at all was changed in ESB from the DVD to Blu-ray, certainly not anything notable.