The defense is good, very very good. If the new guy can talk Greg Williams into staying then half his battle is complete.
Then all he has to do is get the offense squared away and they could contend immediately.
The best options.
1. Kroenke and Demoff convince Jeff Fisher to bring in an experienced OC with great credentials and hand him the offense and not interfere with what he does on offense.
2. Fire Fisher and make Greg Williams the HC with the understanding he will accept an experienced OC with great credentials and hand him the offense and not interfere with what he does on offense.
3. Go out and bring in a Jim Harbaugh or Urban Meyer or Saban or Shaw and ask them to keep Greg Williams as the DC as the defense is very good.
Otherwise a new coach will want his own guys and system and it may take 3 years at least and that is only a guess.
Grits