Seems like they should hang on to him until his numbers start matching his talent level, otherwise Ducks fans will just be disappointed with the return. Regardless of Gibson's skill that contract is risky because goaltending is voodoo, contenders cant afford to take that on without hard evidence of recent success(not saying eye test is worth nothing here but with with only eye test to go off of GMs will not give up premium assets, they will leverage this in a negotiation). The bad attitude/compete due to being on a losing team makes him less appealing, don't know why that keeps being brought up as a point in his favour.
I suppose someone may get desperate and overpay, but the NTC limits that further(likely no Canadian teams) lowering his value in a deal. Lots of time on the contract to turn things around though so might as well let him play to increase his value if you believe him to have that ability, which many Duck fans seem to. Unless you feel he is a depreciating asset (there is an argument to be made here as well)? What's his injury history like? That should be a factor as well.