Conflicts of interest are not simply about problematic relationships with the defendant. They can arise any time the prosecutor has an interest which diverges from the public interest. A relationship to the defendant can obviously create such a conflict, but that's not the only way.
A romantic relationship between Willis and Wade which predated his hiring can create such a conflict, because her choice to hire Wade rather than someone else could be confllicted If Wade was paying Willis for his hiring, that also creates a conflict of interest because Willis benefits financially from both hiring Wade and from pursuing the prosecution.
You can read the full decision here:
A note about what this decision is and isn't. What it is not is an examination of the evidence of the conflict of interest. For the purpose of the appeal, the court took the trial court's findings about that evidence as established. So for example, when the trial court said that there was an "odor of mendacity", the appeals court took that conclusion as given. What the appeals court is doing, the
only thing it is doing, is deciding if, given the trial court's finding of fact, its remedy is the correct remedy. And the appeals court is saying that no, it isn't. Given the findings of fact that the trial court made, it should have gone further in its remedy.
I'm not terribly surprised. The original ruling was sort of a copout. The judge basically said, yeah, it looks like Willis and Wade are liars, and this whole thing stinks. But then his solution of allowing her to just fire Wade wasn't really a solution, because if Willis stinks, then just removing Wade doesn't fix things. The judge was up for election, and he probably didn't want to take that step because it would have hurt his chances. So he didn't. But he still put it on the record that the whole thing stinks. And so the appeals court made the call that he wasn't willing to make to boot her off the case.