well. I wen through that journey as well - started with "I want a server that does everything" too, built Windows 2012 Essentials DC , set up DLNA (using PMS -> UMS ), set up virtualization, cloud backup etc. argued with people about how limited NAS is and how stupid pricing is once you get out of the basic solutions . after a while, what you realize is that one server is that one basket with all eggs, should anything go wrong (bad host OS path, hardware problem, or anything at all) and you are f$cked since you put everything into the same area. also you have a hog in terms of resource and power consumption when sometimes all you want is a small subset of functionality , why keep a supermicro double Xeon, loads of RAM, redundant PSU, monster powered up if I want something 8W device could do for me?
do I still run a server ? yes, I have split the domain controller functions from virtualization lab+playground, moved domain controller to a Qotom device of just enough hardware and power up virtualization beast when I want to lab something or test out RC for various (primarily Microsoft) software. use to also run pfsense for years, went Mikrotik and similarly not looking back. fixed function devices have a very strong value offering if used correctly. Same with NAS, in their niche space - they are awesome. people complaining about them is like people complaining about hammer being bad screwdriver, well it is not intended to used that way - if you want a screwdriver , get a screwdriver. if you want something to expose/server data on your network , get a NAS. By the way, Shield TV now hosts Plex Server (not only client) so that little box could be your transcode for anything/everything. I agree on not wanting to run such things on the NAS.