Keeper is a must as both are not reliable enough. Both have cost us games this year.
As others have said would think a new CH is a must possibly two as still think most are being to charitable to Ash "bomb scare" Taylor. Mind you if Shinnie does go to left back it does free up Considine to play CH.
Agree with Bobby that I would like to see McGinn playing behind Ronney the in the middle.
Having said the above other than a keeper the rest is just tinkering and do think that with a quality keeper we will have a squad next season that really could push Celtic all the way.