I agree, her character should have been more fleshed out....Interesting, I thought I read that in the original script she escaped and got recaptured, and then meets her doom, not escape completely. I could be wrong. There were other deleted scenes with her that I wish they add in, rather than "tweak" scenes. Who cares if the film is longer - Lord of the Rings is like 3hours, no one minds
On the previous stuff - probably they had her grabbing her own chain because it'd be next to impossible to actually have a puppet grabbing and reeling a chain in. I still think she was trying to escape from him (she's really yanking on that chain a lot!), and so it could be that she was trying to take as much of her chain from Jabba, not realizing he would kill her for it.
I think their argument is generally pretty obvious too, but I still haven't actually seen an official translation of it - which is odd considering how every fake language seems to have a dictionary these days.