Most of her commands are easy, but the timing for certain juggles are hard. You shouldn't feel bad at all. Especially for some of her PL that require very strict timing.
Yeah. On the other hand, this is being good at practicing actually inputting stuff in a crisp way instead of spamming the buttons, because you can't do that at all with Kasumi for any of the challenges.
Yeah, like any of her strings with teleports you have to be careful online or you could get the wrong teleport by accident. Sometimes with her strings too, like PP>P>K can come out as PP>PK if you mash lol.
Haha, I love her teleports. I can't help but be flashy with her xD. Honestly, though, her 33K into 66K-K and 4PKK gets as much damage as most of her teleport combos anyway. The only time you really lose big damage without teleports is with most of her PL and grab/hold launchers.
Like PMS_Akali already said, you don't need to do flashy combos all day to get good amounts of damage. Nevertheless, performing combos and juggles is important for her because she does not deal much damage with single moves (And those who may do are hella punishable).
For that reason, playing Kasumi online can be very difficult for newcomers, since they need to get a feeling of how the game mechanics work first. On the other handside, Kasumi teaches you everything you need to know about DOA5, so it might still me good for you to play around with her a bit.
The timing for some combos in her combo challenge is very tricky so you should try to get a feeling of her juggle usage first. I myself for example finished her combo challenge really late, after already playing her for about 1 year (with DOA5 vanilla, and I don't play other characters), so don't worry if you are not able to complete it immediately.
Thanks for your kind words
Ever since the first DOA, she's been my favorite character, so I'm sure playing around with her every once in a while. I'm just not playing her online because I felt from day 1 she was hard (for the reasons previously stated), so I stick to Mila for now which I also love. But I really wanna pick Kasumi eventually.
It also depends a bit if you are more into online or offline play. If you are going for offline play, Kasumi might be even more difficult because frame data is merciless there and you might get butt-kicked a lot because you really have to learn not to use unsafe and punishable stuff that leads you into huge disadvantage.
Online, you might take advantage of the delay, allowing you to be more save and use her speed in combination with this. The bad thing about online for her are heavy input delays and lags that can screw up you juggles completely.