I'd love it if, instead of the current file management interface, I could just use my Dropbox and have it seamlessly sync. That last part is important… I find it pretty annoying when apps force me to explicitly save or move files to Dropbox. I just want a folder that stays in sync with another folder in my Dropbox. iCloud is nice and all, but I can't just painlessly get stuff into and out if an app that way.