It's a pity that Stark and Halibel didn't get to be main rivals of Ichigo. The Espada who fougth against the main character were the ones that got most character development, even Nnoitra.
What makes me believe that Stark will have some kind of appearence is the fact that we have heard nothing from Lillynette yet.
Quite frankly, I could believe in Stark joining SS but Halibel...it just doesn't seem like something she would do, especially after old Yama-ji fried Apache, Mila Rose and Sun-Sun.
I suposse that all I can expect is a flashback and for Halibel to do something that'll really anger Aizen. Maybe stopping him from creating the Royal Key or some kind of suicidal attack.
Now we'll never get to see Halibel vs Yoruichi.
At least, I think we can safely assume that Ice-midget will be really pissed of by this. He'll see Hinamori on Halibel.
Yamamoto should be doing someting useful like dueling Aizen instead of sitting around and waiting for the battle to be over.
Damn, I'm really angry at Aizen. Too weak? If I recall it correctly, her skin had yet to be cut and she was figthing against three opponents. Well, at least this chapter gave me a little idea for a oneshot