I know there is a faction who doesn't like him, but I am not one of them. Gard was a player for Ryan and then an assistant for many years. Bo didn't like to recruit, so Gard (and the other assistants) were mainly responsible for the players they brought in over the years.
As a head coach, Gard's had a couple of early exits from the NCAAs, two lesser seasons, and some recruiting misses that lend voice to the detractors. On the plus side, I think he has 3 B10 titles, including just two years ago - that year they were ousted in the round of 32 by Iowa St. in a game where Chucky Hepburn got injured in the first half and didn't return. The detractors still blamed him for that because we didn't have a good backup PG - to me, it was just unlucky. The tournament is always a bit of a crapshoot.
Is he not as good as Bo Ryan? Maybe true. However, you have to ask if there's a better fit than Gard for how Wisconsin is most likely to succeed (everyone says Tony Bennett, but he has a job). There's a pretty good and somewhat unique formula at UW, and ditching it for the shiny object would be a mistake.