Hi there,
I, too, have been experiencing battery life issues. I also have been having icloud issues. Occasionally, my messages app would run slow and I decide to close the app (by double tapping home button and a flick). However, as soon as I close my messages app, my phone begins to slow down and erases all my contacts and messages once the app is reopened; they all comeback after 10 minutes or so. And worse, my phone then begins to heat up and the battetry drops like crazy. I might have occasional apps open like snapchat, contacts, and safari. No games, maps, or any tracking-required apps open. I got to this page from an Apple blog forum and I hope me sharing this will get some attention by Apple.
I know this is a bug that Apple needs to address so I'm hoping it gets fixed. But I went to an Apple store anyway to see if they have had people come in with similar software issues. The Genius just said, "Have you checked you background app usage? You could have applications that are taking up a lot of battery that might be causing some of these problems..." (*rolling my eyes*).
edit: I have an iphone 5