It's a negative at a place like Georgia, which demands national championships. They fired Richt because his teams had regressed on the field and he didn't have a title that added to his job security to fall back on. Richt was just as good on the field in his first 4 years as Kirby has been. Fair or unfair, Kirby's got to show more (i.e., win a national title).
When you're comparing Richt and Kirby, I think it's key to use consistent timeframes of their careers. Kirby's first 4 years at Georgia look good compared to Richt's last 4 years at Georgia, but I'm not sure that is the best comparison. During each of their first 4 years, both coaches were these young, fresh-faced, great coordinators on their sides of the ball that injected some life back into the programs. Richt was never as good of a recruiter as Kirby was, but he was better than Donnan. Kirby has shown to be a better recruiter than Richt. All the other similarities are there. An install/retool year in year 1, an SEC title and top 3 finish in year 2 (...and Richt would have been in a 4-team playoff had one existed), and then a loss in the SECCG in year 3. On the field, Kirby has achieved more than Richt only in the number of division titles...Kirby made it back to the SECCG in year 4 and lost, while Richt did not make it to the SECCG in year 4 but did finish #7 overall.
Overall, this notion that Kirby is a way better coach than Richt is just a perception in people's minds, not borne out by any facts (so far). I think it's got a lot to do with Kirby being a hardass while Richt was this nice, almost meek guy, plus Kirby is a better recruiter and has played in a national championship game. But remember Richt also would have had a chance to play for a title in 2002 had a CFP existed. If a CFP didn't exist in 2017, Kirby wouldn't have had a chance to play in the title game, just like Richt didn't have a chance to, since they were both outside the top 2 when the conference title games were over.