I've been dedicated to Lei forever now, and he is very hard to learn, for one the amount of moves, then 8 stances, with seperate moveset list for each of those stances. He's almost 8 characters in one. More if you consider each way when he lays down. Lot and lots of hours watching Asano and Tetsuo vids, even BloodRed, n8nmonster and Hattorii vids.. and actual studying as geeky as that is. I'd say you gotta be dedicated to MAIN Lei to master him. Esp at a tournament level. I can HaHa with him natural as anything now though and I have his entire moveset down. I still haven't mastered him, all his safes etc.. Overhand or joystick is NEEDED to use Lei properly. Also, anyone w/ cancels, dashes like Baek, Hwroang, Mish's and Bryans taunt cancel. But as a Lei player all those characters are hard to master no doubt, but do have a very effective basic level moveset to them for beginners imo. Even Yosh. To me Lei has no decent spammable, cept maybe d/b+4,4 which is a horrible honestly or Razor Rush which even that require timing input to step into stance.
It's funny watching new Lei users, hit buttons go into snakes, strike twice, kick at nothing, then fall down on the ground, roll around. You can just tell that his controls aren't basics like other characters. He is definately beefed up in T6 though. Thank you Namco!!! Others maybe hardest but like Baek got his low,low,low..low,low,high string that players can easily pick up and get wins. So I say Lei, I don't use any female characters since Xai in T5 so I can't speak on them.
Easiet to me just to pick up and win with is Kaz or Hei, just cause d/f+4, u/f+4444 or d/f+2 or Hei's hellsweep and their pokes