The main thing is to take redistricting out of the hands of partisan legislatures and into the hands of procedurally neutral commissions of some sort. It's a basic democratic principle: the management of the election shouldn't be in the hands of one of the parties competing in it. I think this is much more important than developing an exact mathematical definition of a "fair" map.
I can understand the existence of criticisms of the various commission-drawn maps, but these criticisms only make sense against the background of a much higher expectation of fairness for the commissions. Any of AZ, WA or NJ would be considered at most a very mild gerrymander if they were instituted by a legislature of the party on whom they are supposed to confer advantage.
Better still is to have the commission sort from publicly generated maps. The MN contest drew 500 submissions after the OH contest had 100 entries. The public can draw good maps, and with some guidelines as to the goals from the commission then the effects of any commission bias can be reduced.
Better still to have the public determine the maps. It is legitimate for the public to have a bias and act upon that bias.
