The reason I've opposed emotionally charged moves against Fulmer is that UT faces higher risks in replacing the HC than other programs of their level. If the guy comes in and does not succeed on the field, he will not be able to credibly raid other states for players and Tennessee does not produce the talent to win the SEC.
No matter how "exciting" a new coach or system is... he has to step in and win even faster than Saban has or else opposing coaches will have a very good argument with recruits that the guy won't survive.