Master Shiori wrote...
I don't think she hates Shep in ME3. After all, you helped her avenge her dead boyfriend and get his greybox back.
The problem is that, unlike most other squadmates, Kasumi lacks military training and experience. She prefers to use her skills and cloaking abilities to avoid confrontation whenever neccesary. But in ME2, you dragged her into a situation where even hardened veterans have a good chance of dying, let alone someone like Kasumi.
So, knowing what kind of a mess Sheps gets into on regular basis, it's understandable that she wouldn't come aboard the Normandy, especially since her skills aren't going to be of much use against something like Reapers.
"I can't break into a Reaper base and steal a big "I WIN" bomb for you, Shep!!"
Now if you needed to, say, infiltrate a Cerberus base and steal something from there (like that server; how the hell did she drag that out without anyone noticing?!), Kasumi would be the right person for the job. But fighting abominations in the ruins of Tuchanka or Thessia? Not really her speciality.
Well no, perhaps not "hates". But there is resentment. And it's not about refusing to join in ME3. I can accept the reason she gives. But it also makes a difference how you say it. Things like tone of voice. She sounds almost angry.
I will admit I'm more affected by it than some people because I headcanoned a pretty deep (but not romantic) bond between Shepard and Kasumi. And the ME3 dialogue is completely incompatible with that. I have yet to find a way to reconcile the two and it's not like I'm not trying. But even without them being BFF it still doesn't look good.
First line (in response to Shepard saying he can clear her name): "What, if I join up? Last time I did that you dragged me into a suicide mission." The was she said this came off as far too resentful. I could see her saying it in jest but she didn't sound like she was joking.
Second line: "It all comes down to this war and you trying to bring everyone into it." Really, Kasumi? This galaxy-wide fight for the survival of all sentient life, this is what
I'm trying to drag
you and others into? We get a bit of a break when Shepard himself calls her out on it. Her response for a kept greybox is atrocious, I won't even think about it. If the greybox is destroyed she gives the "can't steal an I win bomb" speech, which admittedly is the best part of that exchange. But everything else in that 2nd conversation is not only a emotional gut-punch to the Kasumi fan but also a tarnish on her character. Notice too that she comes back to it, not Shepard. For all we know he could've been willing to let it go.
Third line: "There's no way you're recruiting me to fight in a galactic war." Again the tone of voice is the most damning. If the delivery had been more light-hearted it might've made a huge difference.
Playing through the first time I remember thinking Kasumi's reasoning was one of the best justifications a character gave for not joining up. But all the stuff around it is unbearable. If she could've just taken things more in stride, adoped a more joking or just a softer tone, that combined with a few line tweaks could've worked wonders.
You can keep the first line but change to tone to half-joking.
Remove the second line completely. After they finish hacking the terminal Kasumi can go right into her speech: "I appreciate you helping me with the greybox but..."
Change the third line to "I'm not a soldier Shep. I can't fight the things you fight. I can only get out of your way." or something along those lines. With Shepard immediately suggesting work on the Crucible it shows he's understanding of the situation as well.