Yeah, Jax and Kano are the two characters who've surprised me in terms of being really fun to play. I wasn't that keen on Jax being in from a story perspective, but I will admit that he's fun to play. I want to give his Wrestler variation a shot.
I beat Super Shinnok first time with Goro, which was the first (and so far only) arcade tower I've done. As you say, his main tactic is just to spam that bloody annoying beam thing, but once you get close up he's relatively defenceless, and it's easy to just block his beam and stomp him.
I might try Jax as my next arcade run through, actually. Thanks for reminding me. I'll add you later tonight and we can try a few games if you like. I want to get some of those skins that require KOTH and vs. games so if you want to team up for that every so often we can help each other out.