The base wage for a player as experienced as him is around 250K, if the 400K figure is correct it's only 150K more than what he probably should have been signed to, while overs, it's hard to think that any club list would be crippled by such a deal.
I think its the length that's the issue more so than the amount. While I can see why the club did it, I don't understand the thought of a 4 year deal. If it was a 3 year deal it probably would have been a lot more palatable. I honestly cant see him surviving until the end of the contract unless he plays a blinding season next year.