Apart from this, Serviio is now harder to get at.
Disagree - you can now access Serviio Console from any web browser anywhere on your local network, including tablets and smartphones. You can easily set-up shortcuts in these browsers, or desktop shortcuts if you really want to. There is no need for a stand-alone app to be installed on these devices (the app is there if you still want it, but its more for convenience than anything - it is not the main game). It will make configuration and control of headless servers and NAS's far easier (once they get version 1.6). You can also access the console from the internet if you have the know how and you have security in place. So it is far easier, and far more flexible, to get access to configure Serviio with this new approach.
Does Serviio immediately add new files without any user intervention?
Yes, always has had the capability to do this automatically if not instantly. From version 1.5. onward, if your OS and drives support it, files added to your shared folders are near instantly added to your library.