If 32-33% damage isn't enough for you then Mileena is NOT the character for you. Plain and simple. She is not a heavy hitter. She is, however, very good at punishing your opponent's mistakes as well as messing with their head. If you practice with her enough and are good at reading your opponent, you'll find that after you finish one combo there's almost always going to be an opening for you to launch into a second combo.
Example: Obviously blocking your opponents wake up let's you launch into a second combo. But let's say your opponent doesn't use wake ups and just blocks after eating a combo, take notice of if they block high or low once they get back up (more often than not people block low). If they block low, use her overhead combo starter to make them eat anoter big combo. If they start blocking high to avoid your overhead, go into your b+3, ball roll combo starter to make them eat a combo. You gotta be quick though, start using either of these combo starters as soon as they start standing up...like I said, you need to be a good student of your opponent and be able to predict what they're going to do so you know which starter to use. That being said, let's say you go to use you overhead starter, but your opponent guesses right and blocks high: Fortunately for you, her b+3 starter is pretty quick so you can go into it pretty quickly, even coming out of her overhead move.
So yes, 32% is not that impressive, but when you're able to go directly into a, let's just say 23% combo, then your damage output suddenly goes up to 55% just like that.
End example.
I guess my point is this: Yes, her damage output per single combo is not as high as a lot of other characters. However, she has tools to link her combos together which forces your opponent to start guessing what you're going to do and if they guess wrong, they're taking loads of damage. She doesn't need heavy hitting combos, at least not in my opinion.
Edit: And for what it's worth, I think the Mileena thread is great.
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