Apple's move to let users 'side load' applications does have some interesting implications. First, developers can now distribute their own open-sourced apps outside of the App Store. Second, this enables easy piracy of apps that are decrypted. A user could download a decrypted app and load it on their device through Xcode, without requiring a developer membership. All apps are also supported (Objective C, Swift, etc).
Developers still have to deal with UDIDs, provisioning profiles, and code signing, but Xcode will automatically set everything up for you. Essentially, a developer membership is now only required if you want to distribute your apps through the App Store, or if you want access to the latest iOS and OS X betas.
Developer Steven Troughton-Smith notes that you must physically plug in an iOS device to your copy of Xcode so that it properly registers the device for your certificate.
Apple has recently revamped the developer program to include iOS, Mac OS X, and watchOS.