Kitana and sub-zero are two bad match ups that I'm reconsidering.
Kitana's iaf are of no harm to JC. All they do is limit his mobility and slow down the pace of the game, which is problematic if kitana has the life lead. Regardless of that, JC can close pressure fairly well with dash d1. The biggest issue in this match up are kitana's far-reaching strings, normals and d1. This is a very footsie based match up, JC is going to have to play the best footsies of his life (which is why I love this match up). It is important to get very familiar with the space Kitana can cover in this match up; spacing is very important. If kitana is doing iaf and is approaching the corner, you'll even have to do full screen footsies. All that time spent closing in on kitana and seeing it get squandered because of a square wave is a horrible feeling. Once you get in you're gonna get that damage and build that meter without having to worry about some pesky armor move. Just be careful if she has xray, you can duck that up close but at fullscreen it's a mid which can fuck up your dash d1s. Maybe 5.5-4.5 in Kitana's favour.
Now I also play SZ. As a SZ player, I consider Sonya a bad MU. This is because using 224 ice clone if she's crouch blocking can get you punished. 212 is useless against anyone with armor and 214 is generally an inferior pressure string. Standing 2 also whiffs on crouch block. All these things also apply to JC. Granted, JC doesn't have ex cartwheel, a long reaching d4 or a dive kick that blows up ice ball; he still has his second-to-none rush down, b3 and ex nut punch. Be patient, and SZ is eventually going to take risks. He still has that fucking ex slide which can put you in the corner though. At the moment, 5.5-4.5 in SZ's favour.
I'm using .5's because we're allowed to in the MU chart, if we ever get around to doing that.
Sonya's another one I'm reconsidering. Initially, I had a tough time against her because I thought her footsies were godlike and her ex cartwheel annoying as hell. Now I think her D4 shenanigans aren't so bad; it's the only way she can get her offense on JC anyways. Ex cartwheel is still a bitch, so 5.5-4.5 sonya's favour.
Of course, it's very much possible I'll change my mind on these MUs within a week and consider them all 4-6.