I suspect the player himself won't come.Cech is leaving on a free and Mourinho can't stop him going anywhere. He is an upgrade on Mignolet and we should be looking at him. If someone becomes available that is better than what you have then you should be looking to get him.
Whilst it may make sense short term I think most players (& certainly their agents) are savvy enough to know that if they've become a hero of sorts for a club over a long period, then moving to a club those fans hate blows a lot of financial opportunities post playing career.
Whilst it wouldn't really effect a decision in the midst of a career, when it's close to the end of it I think that will have an impact on any decision.