We'd have a better chance of pulling off a major draft-day tradeup if we put Hester on the block rather than Briggs, IMHO.
A lot of Bears fans would be really upset to see either of those guys walk, but I'm almost certain Hester would bring more in value than Briggs at this point.
The problem with trading Briggs is that it pretty much forces you to go right back to the draft to fill the hole you just created (as in that Bleacher Report scenario)... and then that's a pick you can't use on another position. And if that rookie didn't step right in from Day One and play at Briggs' level, we'd be hosed. Whereas with Hester, presumably we'll be phasing him out of the offense anyway and we do have other guys on the team that can return punts even if not at a Hall of Fame level.