As for Herman, is the sample size small? Absolutely. Is there risk? Absolutely. BUT let's at least evaluate his tenure at Houston:
Record: 7-0 (4-0)
Performance against P5 teams: 1-0 (@ UL) [Next game against Vandy]
Average Margin of Victory: 27.9 Points (not a typo)
Houston in 2014: 8-5 (5-3)
cfbstats.com - 2014 Houston Cougars
Points Scored Per Game: 29.8
Total Yards Per Game: 414.0
Points Allowed Per Game: 20.6
Total Yards Allowed Per Game: 343.4
Houston in 2015: 7-0 (4-0)
cfbstats.com - 2015 Houston Cougars
Points Scored Per Game: 47.6
Total Yards Per Game: 561.1
Points Allowed Per Game: 19.7
Total Yards Allowed Per Game: 362.0
One more thing, one of the things I find risky about Herman is that Houston wasn't a dumpster fire when he stepped into it. Houston was a decent program, won their bowl game last year and did okay. All things considered Houston, for a first time HC, was a pretty good starting point. It wasn't a dumpster fire like Memphis or SMU (Morris).
In Summation: What more can Herman do at this point? He is 7-0 and raping his competition. Is he risky? Sure. But at least, based on the sample size so far, he looks pretty darn good.