Ideally, wheels should already be in motion regarding reinforcements. Targets should already be identified, contact with clubs should already have been made. There is nothing preventing clubs from negotiating transfers mid-season.
Having said that, I think it is fair to say that Draxler looks very likely to join us in the summer. It would be extremely satisfying if we, for once, could have our transfers sorted early, preferably before the WC. Wenger seems to have this dated idea though that everything should happen right at the end. Yes, I think it is mainly because of Wenger we have been operating like that.