Please, DON'T kill off Veers. While I think "original ideas from the screenplays" are probably the least objectionable things to add, I don't think that just because it was an original idea means it has to go into the film.
I think it's great that we don't know the fate of every single character in the series. Not everyone has to be killed on-camera, and the Rebels do enough as it is. I always liked the "exploding head" on the AT-AT.
Don't modify the Ion Cannon... it's the first and only one we see in the series. Turning it into some sparky effect or changing it is just stupid and unnecessary.
The Imperial presence at Hoth doesn't need to be increased, because the Rebellion is small... the Empire DIDN'T send their entire force to crush the Rebels there, because they didn't need to! If anything, the rest of the Imperials were patrolling the rest of the galaxy. Besides, if we expand the presence too much in ESB, it'll diminish what we see in ROTJ (which still wasn't the entire force). ESB was just supposed to be showing us a lean, elite group of Vader's that was going to find Skywalker.
I'm for minimal changes to ESB. Other than fixing color gaffes and Special Edition excesses, is IS "danged near perfect" already. Splicing in the ROTJ Emperor in the hologram scenes with the original lines is one change I agree with (so long as it doesn't look too obviously recycled).
But trying to throw in Prequels references, "extend" the battle, and so forth is just fanboy-service, it won't fix or improve the film. If Adywan wants to put some stuff like that into "deleted scenes" on the disc, that's cool, and the fanboys can make their own edit to splice that into the film itself. But he made the right choice with putting say, the "extended Alderaan destruction" into a deleted scene instead of the movie proper.
Recoloring all the ships and blasts just seems pointless. Why does ESB have to change to match some other source or interpretation?
Too many people I think are going off on how many unnecessary things they can get inserted into the film.
Lucas himself did this with ANH and ROTJ, but he made the fewest unnecessary changes to ESB. The ones he did do tended to stick out as stupid.