She's also missing her hax boot, so I am guessing this normal Okuu and not OPkuu. Well it doesn't matter though, nuclear or not, Keine can just erase the fact that she had nuclear and bam, useless idiot.
But she still has the Yatagarasu eye on her chest so she still has nuclear power. Beyond that, it depends on whether the arm and leg are something she summons or something she can take off and forget somewhere.
Either way, with Flandre and Okuu in the same class, I expect fireworks.
I'm betting shino read/watched KareKano after looking at this. Okuu reminds me a lot of how Tsukino and Kano were carrying on in chapter 8 of the manga. So cute... XD;
Koishi's expression in the last panel made me think to put this under 'False Smiles'
*flaps**flaps*You seem happy, Okuu.But, but, Koishi-sama! It's school! You always seem to have fun there on your own, and I've really wanted to go too!Wow! What kind of place is it?This is... going to be fun...SCHOOL!!!What do you do at this "school" place?Huh? And why do you go to school in the first place?Heh heh, she's so happy and lively, this should be fun.