There's really no way of knowing if this was a good or bad hire at this point. That likley won't be known for a couple years IMO. It at least looks much better on paper than the hiring of Mike Jinks, that's for sure. I'm guessing Loeffler's staff will be much better than Jinks' too as not only did Jinks have very little collegiate experience, most of his staff didn't either. it was a recipe for disaster - and it was one.
That said, (Jinks aside) the last several BG hires have all been very good with many of them generating little fanfare. When BG replaced Gary Blackney with an unheard of, first-time head coach who was the WR coach from Notre Dame, no one knew who he was. He took over a team that finished 2-9 the previous season, had all kinds of off-season attrition, and in his first game as coach took BG on the road and beat Missouri and the rest is history, So yeah, I'd say Urban Meyer worked out okay. They had some success under Gregg Brandon (replaced Meyer, was on his staff). Then when they hired Dave Clawson (coming off a poor year as Tennessee's OC) many questioned the hire and all he did was build and improve BG and they became MAC Champions. In 2012 Clawson came right out and said Ohio was the team BG was chasing and striving to beat. He said they wouldn't be MAC East champs until they started beating Ohio. Boy did those words prove true. Once BG started beating Ohio, BG started winning the East and started winning MAC Championships. Many people knew of Dino Babers and he sustained BG's success, but he really benefitted from the offensive skill players Clawson left him (many of them were underclassmen when they won the title under Clawson in 2013) but the defense that Clawson built went right out the window. BG won the MAC Championship again in 2015 under Babers but BG lost a massive amount of talented players after that season and Babers' weak recruiting classes, coupled with a guy like Jinks coming in way over his head, led to a huge fallout.
The biggest key for Loeffler at this point will be to hope no players transfer at this point. With the new early signing period just weeks away and all the decommits BG has already had with the coaching change, he's up against it right now. Ohio and Buffalo will be the teams to beat in the East again and BG won't challenge either, and they can't ever get past rival Toledo, plus they have another pair or Power Five games in the non-conference. It's going to take a few years to assess whether this was a good hire or not.