2. I was referring the horrific physical transformation she went through in being turned into a drone. I think that would leave her a little shaken to say the least. You don't just recover from something like that without a little trauma.
You're not considering their mind set upon assimilation.
Picard wasn't prepared for it, the Borg took him against his will.
Janeway gave herself to them willingly. She was already mentally prepared for the assimilation and de-assimilation process. The Borg bent Picard to their will, Janeways mind was never fully connected to the collective. So Janeway her will was still her own. Unlike Picard or Sisko, Janeway didn't fear the Borg. Thanks to Picard and other captains that faced the Borg, it gave her enough insight to know how to circumvent them.