Sorry for the bad experience, sounds horrible. I'm going to OGG in April and am very excited about it. Of course for me it's free so I could care less how comfortable the seats are.
The weight problem is being resolved. Yes it is just a matter of filing different paperwork and from what I read in our employee newsletter, they are doing that as we speak. The flight does not take weight restrictions all the time, I've seen it go out completely full many times. Yes the cargo does make a lot of money, but still having to bump many passengers is not good.
I'm hoping they will remodel the interiors of the 757 cabins to make them more modern like the Airbus. However I have no idea what the plans are for that. They did say remodeling would be done as it was needed....it sure is needed on those planes! I flew FC a couple of times on the 757 and found the seats just fine....except for when I was trying to sleep and my pillow kept falling in between the seat and the wall....that was a pain.