Cumulatively over the last three seasons of goalies to play minimum 1500 minutes (72 in total), Gibson is:
65th in GSAA
3rd in xGA
1st in HD shots against
23rd in HDSV%
15th in rush attempts against
I think two things are clear with Gibson:
1) He is no longer an elite goaltender and has now become an average goaltender who MIGHT still be capable of stealing you games
2) He clearly does not give a single shred of a shit playing on the god awful Anaheim Ducks, who seem like they have been in a state of rebuilding for over half a decade now and getting pissed on by team after team nightly (see: Toronto, 57 shots last night)
I would not be willing to take the risk that he might still be the guy he was early in his career at that cap hit.