It's not just lately, it's been the whole time Potter has been eligible. He's just not as familiar/experienced with the rules of the Wisconsin defense, so in crunch time, yeah, they go with Reuvers. Potter is a better stat-stuffer when he's in, but the team's defensive efficiency is quite a bit better with Reuvers. Like Pikiell, it's defense-first with Gard.
I would say the biggest beneficiary of King leaving has been Ford - although he's been a starter all year, his role is much greater than it was, and he's stepped up to play his best basketball of his Badger career.
None of the players are really stars, but all of them can and do contribute (5 different leading scorers over the 6-game winning streak). It was indeed a process to wean themselves off of the way they played with Happ, and they tried to plug Reuvers into that role and he just doesn't have that skill set (few do). The offense with Happ and now without basically have the same efficiency numbers even though they get there different ways. That's called adapting to your strengths, and that's why Gard does deserve some post-season award consideration.