Bad move for him. Would've thought he wants to see out his days playing. One of the recently promoted clubs or a competitive championship club would suit him well.

Wayne Hennessey's biggest problems were that he wasn't Speroni & was never a crowd favourite. Sections of the fanbase were quite happy to turn a blind eye to a number of Julian's mistakes towards the end of his career, mistakes for which Hennessey would have been castigated. He also got a raw deal in having to play second fiddle to the vastly overrated Steve Mandanda, a player who never looked fit.
Good luck to him if does get the 3rd 'keepers shirt at Chelsea.

I think that's a little unfair to Roy as his instructions from above were to stay in the Premier League at all costs and here are some old boys to do it with whilst Vieira's remit seems to be totally different

Let’s see how he gets on, it’s a very difficult situation with a very tough opening 6 games.

Not sure what draws you to that conclusion. He was 1st choice for a number of seasons and played regularly. Last season, he got a bad injury playing for Wales in the early part of the season. Hence, Palace bough Jack B as the back up goalkeeper at a very good price.
In my view, Wayne has been a loyal servant over a number of years although both parties now recognise it is time to move on - all thoroughly amicable as far as I know.