I'll be throwing confetti if iOS 10 will let me run two Excel spreadsheets side by side. That's kind of a big deal to me, which is sad in a way...both for me and for Apple.
Well, you have an option here: use excel and open up numbers. I know, I know. That's pathetic. But hey if you keep waiting for that option it's like asking my father to fully embrace my brother Tyrion.