Who exactly would she fight?
Juubidara can kill her whenever he feels like it, on top of that she's practically out of chakra so her returning to the battlefield at all would actually be an unwise decision.
In fact the smart thing to do would be if Obito kamuis Naruto alone out of the dimension and just him and Sakura would be left (That way Madara won't get his hands on the other rinnegan)
I didn't say she would fight someone in particular. I said " I hope she will help in the fight ".
I don't really care in which manner she would help, but I would like her to help.
I would like Kishi to do some team work, and by any chance, some team7 team work, even if Sasuke is still corrupted in a way.
We still didn't had it, even if team7 reunion looked nostalgic, they didn't fight alongside for a long time, it was really brief. So I think there is a possibility that Kishi might want to continue this. I would like that.
I would rather prefer that than Naruto going alone against Madara...
About what you think would be smart, I have to say I hope nothing like that will happen. That would be too simple and really tasteless.
Moreover, I can't see Sakura letting Naruto out to fight just after he escaped death. She would protest.
And obviously there will be a problem with DZ...