I think we'd be insane to sell Bainesy regardless of the price. He's undoubtedly one of the best left-backs in Europe. People say Cashley has been the best in the world, and Bainesy has easily been as good as him in the last few seasons, so I really don't think it's over-stating it to say Bainesy is one of the best in Europe in his position.
So whoever the replacement is will be a worse player, without question and so the team is weaker. Also Bainesy is amongst the highest chance creaters in Europe over the last few years, which is often statistically demonstrated by Opta etc from left back!
Also he loves the club, and has never agitated for a move (so far as we know) ever.
If we're going to sell to strengthen the team, which is regrettable, it's got to be Felli. He wants to leave, whether sooner or later and he is MUCH more replaceable in our team. It makes much more sense in teams of money, team unity and rebuilding.