It's disappointing to lose a player with the talent and potential ability he has, but it's certainly not the end of the world.
He's not even had a full season in L1, and since returning from injury he's hardly set the world alight. It's a suprising move for Norwich, a team involved in a relegation battle - is he a signing with next seasons championship in mind? Or if they survive will he be sent on loan next season to gain experience? In either case, it's a strange choice on JM's part too.
In terms of replacements, let's take the worse case scenario; we don't sign anybody new over the summer. From the existing squad, both JC and RL are more than capable of playing 10, and both only require a contract extension.
I don't think we can equate this to the Wilson situation, he was more of a proven talent when he left than JM, and he only needed to step up one league.
I'm not intending to dismiss JM and his potential, because it's clear to see he has bags of it, but he's replaceable and, for all extents and purposes, still unproven as a footballer at professional level.
Of course I would prefer he wasn't leaving, but he's an 18 year old that's played a third of season in L1. Not a proven cult hero. It's an emotive, dissapointing piece of news, but let's keep done perspective.
I wish him well and I hope he realises his potential, rather than becoming another waste of young British talent on a premiership bench.
I also look forward to him returning to us as we bypass Norwich on our way to the premier league.