My main problem with Office, of any version, is the same problem I have with Windows. Every new version is simply a game of Hide the Hamster with all of the features I've known how to use for years. No, nothing has been "lost" in the sense that it's all still there. It's just reshuffled endlessly. Supporting different versions of Office just means doing a lot of Googling for stuff like "This or that feature, Office 2007" and "This or that feature, Office 365." It makes acquiring any sort of fluency in the technology almost pointless. Why bother? It's just going to be somewhere else in the next version of the software, which should roll around in another two years or so.