Maybe you have burned out on this game for the time being. I mean, to get that rank you must have played about 250-300 matches with that character, right? I'm still at 7th dan with Lau, and that is about 150 matches played.
As for Akira, yeah, I'm well aware that he was in the original game, but in terms of character alone he must be the most boring character ever in a fighting game. I'm sure he is good to use once you learn him, but for me, he is bottom of the list of characters I want to learn. Next up I'm thinking maybe El Blaze, or Goh.
I went and played a couple of matches in the arcade buy got owned: primarily because the arcade button layout has the kick and guard buttons reversed to the way I have my HRAP3 configured. Really don't like that layout, but seen as the arcade doesn't enable you to map the buttons (why not?), I remapped the HRAP3 buttons to match the arcade layout and have since been getting more used to that. Still not there yet, but next time I hit the arcade I will be able to put up more of a fight, and not hold down the kick button thinking I am guarding