protosam Thanks for your feedback. It just so happens that our developer Franz is working on a web installer that makes it possible to install Flarum from a php file. We definitely agree that this is the simplest and most accessible route.
As far as composer goes, like Davis mentions, it's a useful manager for php dependencies. Being cross platform is another bonus. It really does help to ensure that Flarum and its dependencies are up to date without overcomplicating the process, that ability is just a composer update away.
I hope you can understand why we chose composer to help with Flarum's packages, and will stick with us until we have a Web interface for installing and upgrading. We do want to make Flarum user friendly, it's just during this beta period that it makes more sense to use composer directly rather than to distribute zip files or roll our own package manager.