1.) Apologies if I missed someone else stating this reason... Not to mention, one might think that she would've been another Chiyo, Asuma,..., Hanzou-like failure who didn't want to fight for Kabuto and by proxy Tobi; thus, she would sit there doing everything she could to reveal her jutsu and how to defeat herself as well as impeding her own moves making herself as ineffective as possible. It seems like a waste of his resources unless he could really get her to fight full out. Granted she would've been better at the beginning as part of the ambush squad with Sasori and Deidara, but she was quite effective in the assault and recon on Konoha, so she's fairly dynamic when she wants to be. Desire being the key.
2.) As well, other people have made a good point that Kabuto may have had his pieces set since we don't see a powerful fighter of Akatsuki like Kisame whose DNA ought to be all over the place, including his notes sent with his blood and saliva on them. Thus, it could simply be a timing issue.
3.) Really, it seems like Kabuto could've brought more back but didn't, and I think Kishi simply had a limit on how many to bring back, and she had a recent appearance in the manga as did Kisame while alive, so there was no need to bring them right back. Edo Tensei was sort a history, from short-term at the beginning to long-term at the end, now going all the way back to Madara. Ironically, it seemed like each generation going backwards seemed to surpass the newer one, but that may have been the ninja chosen and Kabuto's mastery of Edo Tensei, along with gaining more of Orochimaru's chakra, and by proxy his power.
Peace
Peace
