Wow, never noticed him in ESB. As Leia seems to be using the Captain is the last man to abandon ship protocol on Hoth, I could see other rebel leaders waiting until the last ship goes out even though that increases the chances of not escaping. I once read someplace that Rieekan was supposed to have died in ESB, (which left Leia running things when Han shows up to get her) but was that ever filmed?
It is in the fourth draft (which seems to be what filming started with), but no telling if it was filmed or survived to the (regrettably unsurfaced) fifth draft. The Making of ESB seems to outline a few differences, namely a couple of Cloud City scenes that seem to have been filmed but later cut for budgetary reasons (it would have been shots requiring matte paintings and opticals).
As Rieekan dying takes place when the command center gets hit, it seems like that scene would have been cut from the schedule due to how much more difficult it may have been to actually wreck the set on camera, rather than redress it to look destroyed. I can’t imagine they would have filmed something like that and cut it. The script didn’t change much aside from cutting out a part when Han and Leia acknowledge his death.