I made a trial account for nostalgia, and the servers actually feel fairly alive again. There's peeps in the training bgs doing quests and taking the main keep, real keeps trade hands every night (along with control of DF), and even remote zones in SI (Faraheim, Moderngrav, Griploska Mountains, etc.) where I like to disappear have people wandering around in them. The servers are all linked now to a single frontier (maybe it's been that way for a while, but I've also been gone a while), and you can transfer between any of the servers instantly, so I think that helps a little.
If anyone does decide to pop on, I'm Hrontir (Midgard). Cheers!