I might ask for an Escape Artist check with a -4 penalty for each size above Tiny the weapon is. The great sword might be entangled in the net with the PC, but with no leverage or room to weild it, the sword becomes a liability more than a benefit. Meanwhile the PC could pull out a dagger and try to slice through it much more easily but it may take 2 rounds to get out as the dagger is only 1d4. I would allow strength bonuses to the damage too, but that's just house ruling it.
[edit: wasn't done yet...]
I have had the whole "net issue" pop up before, where the PCs wanted to just slice down any nets coming at them, which could happen, and I had to house rule an entire encounter of Lizardmen with nets that were trying to capture the PCs. Without any books in front of me now, I do remember looking for anything on nets and sunder or anything like that in 3.0 after that session, and couldn't find anything definitive. If there is something I would definitely like to know, but as far as the rules go a net either hits or misses, and a PC doesn't have the chance to swat it down or slice it in half as an AoO if she sees it coming at her. And once it does hit, there is either Escape Artist or Str check, and not much on weapons if I remember correctly.