Darth Chronus said:

I think the part of that gantry that Vader sliced through (after being slightly cut by Luke - ''Argh! Aaargh!'') should have some sparks coming from it after Vader goes on to 'attack' Luke.

By the way I don't normally advertise my YouTube videos - but here's my latest - http://www.youtube.com/watch?v=Ce07wUVsBHU

It's a music video re-edit of one of my first music videos that I made back in 2006. It includes clips from the masterpiece that is A New Hope: Revisited and also some taken from the TESB:R trailer :)

I think someone made a mock up picture of glowy hot metal saber cuts during the Vader/Luke duel. I'm too lazy to locate them in this thread though.

On a similar note, I recently brought up that I would like to see a glowing saber cut on the bottom of the AT-AT, when Luke is tossing a grenade inside. Somewhat similar topic you can say.