The new changes to the precision tree basically excludes mages from using this tree. As long as you use this tree you are forced to have 9% AS, which is entirely useless for mages (except Azir). It isn't this much of a problem for other combinations - it's good for damage dealers to have some health, and it's good for tanks to get some adaptive force, but this isn't the case for AS on mages. If mages use this tree then they are basically losing half of the bonus. You should definitely keep the adaptive force when Precision is used as second tree.