I bought a dell Vanue 8 pro for work and it runs windows 8.1. I have been using iOS exclusively since the original iPhone was launched, and I consider myself a power user. But two features that Apple needs to steal from Windows 8.1 are:
1) two apps running side by side
2) live tiles
Now I use "steal" in quotes, because I'm referring to the Steve Jobs quote "great artists steal." By steal I mean they shouldn't implement these features in iOS verbatim, they should take these two concepts and Apple-ize them. Make them really work.
Because it is refreshing to turn in my tablet and glance at the stock tile or the mint.com tile and get instant info without even opening the app. I don't care what anybody says, it enhances the experience of the tablet.
Likewise, it is refreshing to be able to have twitter and a browser both open at the same time. I think the way Microsoft implemented this feature is confusing and tough to use, but once you get the hang of it it does feel very refreshing to be able to do it...or at least know that you can if you want to.
Apple needs to hide these features as to not confuse your typical "non-pro" user, but enable it for those of us that want the option.
If Apple adds these two features, especially side by side apps on an iPad pro, I think it would take iOS one giant leap closer for many people to replace their OS X laptops.