I read the motion but don't have time to read the cited authorities. But my impression is that it is likely to be granted. JS either showed an appearance of impropriety (IMO no
actual impropriety occurred, but an appearance is sufficient), or else the only way to prove he did nothing wrong would be for him to testify about his communications with MD, which is not going to happen (or for MD to recant, which is even less likely to happen). No one at that court is going to want to fight the battle to keep JS on the case, knowing that whoever is the judge is likely to have to deny lots of defense motions and rule against the defense on lots of evidentiary issues. If JS stays on as the judge, every one of those rulings will be listed as further evidence of how his "bias" affected the case. ("OMG, he denied 97% of our (crappy) motions! He's so biased!")
I agree that it is normally a risky strategy to move for recusal of a judge, because (1) if your motion is denied, the judge gets pissed, and (2) you could end up with an even worse judge. But that's only if you think you have a chance of winning the case. Here, the defense must be extremely concerned about a conviction, despite the public bravado. I personally believe that the defense in this case WANTS this motion to be denied. Then they will file stacks of silly motions, which will all be denied. Then, on appeal, they can say, "He was biased to begin with, and then after we asked him to recuse himself, he just LOST it and ruled against us on EVERYTHING." But if the motion is granted, the defense can go out to the media and parade this as a Big Win. Lose=win, win=win.