I think there's a better chance that he turns it around than you getting back anything of value for him.
Wentz has been okay as a fantasy QB this season and will certainly surge forward once DeSean Jackson finally returns (because Jackson doesn't drop so many balls), but I wouldn't make that trade.
Which QBs are available as FAs today?
If you can grab a top 12 guy, you especially shouldn't make that trade.

Josh Allen just came off his bye week. Is he available?
Winston is heading into his bye week. Did he get dropped last night?

Neither of those QBs is as good as Wentz as an NFL QB, but they're both very good fantasy QBs.