Doesn't matter how good a Leifang player you are, she is not an offensive character.
66T:
Offensive hold that's very useful. No doubt about that.
236T:
Offensive hold again, also useful, obviously requires more skill than 66T, especially if you want to overtake a skilled opponent with the timing, and also want to take advantage of environmental damage and so on.
These offensive holds however, although nice, do not make them more special than any other offensive holds that other characters have. They are useful, and that's it. In fact, she NEEDS them to be any sort of real threat while on the offensive.
2H+K:
Ah. The extremely overrated low. The only real use it has is distance poking. Nothing else. It's the worst slow speed low of the entire game. Even on HCB it only gives +6 guaranteed which is a crappy stun. And it's linear, while most other lows of this speed are circular, and doesn't give a sitdown like so many other 2H+K. +6 gives you pretty much nothing to follow-up with since it not only pushes your opponent too far away, it only adds to the risk of being sidestepped, crushed or grab punished since Leifang is quite linear and her safe moves are mainly highs or extremely slow.
214p:
Great move for counter hitting since it's actually quite evasive and has decent range. Sure, it leaves you at neutral on block, but she has the same problem as above in that case, meaning following up after it puts you at risk.
She simply is not an offensive character, and it's reflected in her moves. Her OHs and crushes scream counter character, especially since if any of them is blocked, you're pretty much screwed. In DOA5 it was different, but in DOA5U she has to play defensively almost all the time. Like StrikerSashi said, her best tools are ridiculously unsafe, which means, you have to use them as counter moves, not while being offensive.
1P:
One of her greatest crushes and gives a good stun, except you're setting yourself up for a 50/50 mindgame on block. Free cancel/unshu and get grabbed, or use second P to compensate for that, and get grabbed if you were wrong?
3P+K:
Great crush and launches for great damage, but if it's blocked, prepare to lose a lot of health.
It's the same story as those two in general for quite a few of her other moves, or, you have to use highs with the risk of getting crushed. All in all, her strength is defending, and making an opponent too afraid to attack you will get you in trouble. If it's a knowledgeable player, they'll be looking to grab you, and your OHs go out the window. You need some attacks from the opponent to work with. Blocking opponents are trouble.