The way he handled the NCAA investigation, the way he took far too long to get rid of Hewitt, and a relatively poor basketball hire are the main reasons I can't really think about him in a positive light. He seemed to do well in raising funds for facilities and not much else.
NCAA Investigation: He was kind of in a "damned if you do, damned if you don't" situation. If I remember correctly, we were punished not because of the crime, but because the NCAA told DRad not to tell CPJ and his staff they were being investigated in the first place. Well, if he did that, he would have been at risk of losing CPJ's trust. He only has to deal with the NCAA for a limited amount of time, he would have to work with the guy he hires every day.
Getting Rid of Hewitt: Hewitt had a self-renewing 7 year contract. The buyout on that one wasn't something GT could easily afford, and certainly not something to you go to donors to fork up all at once. If I'm not mistaken, it took several years of banking donor pledged money to swing the buyout. GT athletics could have been crippled from that, to a certain extent we're kind of still recovering from that as our last two basketball hires have been influenced by the buyout.
Hiring Brian Gregory: Could he have done better? Probably...but how much better considering the above? We'll never know, but hiring CBG is probably a negative in DRad's column.
All in all, your biggest complaints against DRad were really almost beyond his control. Can't really blame DRad for BayBay taking merchandise to get us in the situation in the first place, and DRad was stuck in a lose-lose situation no matter which direction he went on telling the staff. DRad also didn't hire Hewitt, and he certainly can't control GT's financial state to buy Hewitt out...that took time.
I think DRad's positives far outweighed the negatives. When he left, he certainly didn't leave to the all problems coming to light that MBob is leaving behind. Think of his capital projects this way: UGA with all of their money and fanbase could not get an indoor facility until recently. GT, with our shoestring yearly budget, and in a location where adding real estate projects are 5-10x more expensive than in Athens, got an indoor practice facility many years before UGA did. DRad had the foresight to do our largest capital improvement projects when interest was almost close to zero. He was also very good with getting our notoriously cheap alumni to fork over a lot of money to help with those projects...not to mention buy multiple coaches out (Hewitt, Gailey). Oh, he also hired CPJ...
I would take another DRad 10 out of 10 times before another MBob or Braine.