We're fighting TWO Hollows.
We got injured fighting ONE.
We have Rukia to keep the pressure off of us.
The moment we pull out Nejibana Rukia WILL become useless. We'll have to defend her AND fight both Hollows at the same time.
If you really want Aizen's attention that much - if we were to believe his own ramblings, he is watching Ichigo quite a lot - then don't attract it in the middle of f****** combat, when our backup hasn't arrived yet, and the one useful person we have is horribly traumatized and will break down when we pull out Nejibana.
At least have the decency to be consistent. The majority voted to bring Rukia here, because we wanted backup. Now, you want to make the backup useless to, what, show off? You realize, of course, that we can simply ask Ichigo to train with us, have Rukia be there, and release Nejibana during the training? Or, hell, why not simply ask Rukia about her own Zanpakutou, most likely surprising her, and giving us the perfect opening to tell her its name?
Dear God.
These are the people who want to play a tactic-focused character?