I don't bear him any particular malice, seems we didn't want him and Chelsea was the only offer on the table. He wanted to come back to the PL so he took it.
For our part, there are positions we need strengthening more than midfield but it would have been a statement of intent to re-sign him, a sign we mean business and are serious about pushing on and competing for the title next year. And maybe we are and some proper marquee signings are coming but it's pretty sickening to see us standing by and letting a team we're supposed to be trying to compete with strengthen.