I know adding ReplayGain and/or volume leveling support is more of an advanced feature. As others have stated, when shuffling music with varying levels of loudness, this feature becomes essential to ensure a smooth listening experience. Most users probably don't even realize the importance of this, but I'm sure most would appreciate it if it's implemented.
To make it more user-friendly, why not have Plex analyze the volume normalization information for each track/album when music is imported into the library? This way, even if users have no idea what ReplayGain is, the data is already present in the Plex database. At that point, the user would just need to enable the option in their Plex client's settings. There would be no need to worry if ReplayGain tags already exist in their music files. The R128 algortithm (http://r128gain.sourceforge.net) is widely adopted and used by many other popular music players.
Adding this feature would be a huge win for users who use Plex for music listening. I can only say that Plex just keeps getting better every day! Thank you for all that you do!!
