Let's look at the facts shall we:
Firstly, we have no evidence that such a huge fee was paid out for a player who was (and still is) completely unproven in the Premiership despite being a national hero in his homeland, so the hysterical comments to the effect that the money has been wasted are quite probably wide of the mark.
Secondly, the club have made no official statement as to whether or not the player is to be released from his contract this summer. Arsene Wenger has commented today that he is "undecided" as to the future of the new Japanese goal-scoring hero, but then it's par for the course for the man to play his cards close to his chest, especially during this period when a considerable amount of horse-trading is taking place.
Thirdly, could someone give me the name of a player released by Wenger that has gone on to be a real success at another club? - No? - thought not. What we have to remember is that "Arsene knows" and I for one will be happy with his decision as far as young Junichi is concerned whichever way it goes.