He's making the right decision, I think he will suit the German league and really has the opportunity to make a name for himself. The lad wants to play football, if he stayed here I doubt he would start more than 15 games for us across all comps and at 25 that's not good for his career.
I'm really disappointed that the club offered him a new deal but I wish him all the best, he's blue through and through and has a fantastic attitude. Good luck Jonjoe.