Leicester, let's be brutally honest here it's made worse by them having the peak of their success at practically the same time as the peak of our decline.
We did, it was a bit later than this year's tournament. I think they left for it after the FA Cup 4th round (which was played earlier than usual at the beginning of January due to Man United playing in the club world cup)
One of the underlying causes of this is Torp, early season he was willing to move into spaces and take the ball with players nearby, he's not doing it at all now.