i'd drop Ali and Buttler
Think of all the good offies over the years and one thing they've all had in common is being able to blend movement/drift with impeccable control - Ali simply doesn't have the control and after nearly 18 months of test cricket doesn't seem to be improving on it either. If the ability to impart a bit of control as well as chip in with valuable wickets falls to one of the seamers I think Rashid has got more to work with moving forward and could be more of a weapon for England in the future
Buttler, well enough has been said and it's obvious he just needs a break to refresh, gather his thoughts, maybe go express himself have a change of scenery in the Big Bash or something. He'll come back, far too many people speak so highly of him and it's evident the talent is there. Doesn't strike me as being afraid of some graft to sort it out either.