First thing I would do would be to do a thorough evaluation of the coaching staff. I wouldn't aim to fire anyone, but tell them what they are doing wrong and what they are to do to fix the issues. It is very vivid what this coaching staff is NOT doing; one can't tell me that the many starting lineups is not the source of our failure thus far. Guys still don't know when and where their minutes are going to come from; and a lot of the players are not playing loose, because they are too busy looking over their shoulders. Second, it is very evident that this ROSTER is not built for the TRIANGLE. We don't have one player that can play without the ball. All of them are ball dominant players and have been so since the peewee league. It is STUPID of FISHER to fathom that these dudes can suddenly change.
We've lost countless of games so far, mainly because of FISHER reliance on guys to run the right TRIANGLE plAys instead of calling a particular play from the sidelines. I don't know if it is because he simply is not a play caller, but if that is the case, he is not suited to be a HEAD coach. As a coach, there are times when you simply have to forego a system and operate outside the box; which I have yet to see from FISHER.
Second thing Phil must do is creatively find ways to clean this roster. After 21 games, he has enough of a sample to know that the roster needs a serious jolt. Trade Amare, Bargnani, JR, Shump, Priggioni, Dalembert,and Cole. Bring in as many quality players as possible and try to pry away some draft picks.