It looks like he will be inheriting a pretty bare cupboard. So for me, the measure will not be wins & losses.
It will depend upon:
1. Recruiting - you just can't have success wo the players. He will have to show right out of the gate that he can attract talent on his own.
2. Effort and Hustle - he will have to show motivational skills regardless of the talent level he has to work with. No excuse for a team not playing hard.
3. System Flexibility - he will have to show that he can add more dimensions to both sides of the court. The offense will need to be expanded. The Zone will either have to prove that it can still work in the modern game or it will have to be scrapped. Regardless, there will need to be alternate D's available for times when the primary D breaks down.
4. Drama - the program will need to not have any off court issues during what will probably be to a greater or lesser extent a rebuilding process.
If Mike can achieve the above then he should get about 3 years to translate that to W's. If he can't achieve the above then the leash should be very short.