I re-installed this and I've been having a lot of fun. The game is old and a bit clunky as expected, but it was a blast back then to create characters and run around Paragon City and it still is to this day.
I made a tank ninja cyborg type of character and I'm having fun soloing everything. They made a bunch of new ways to tackle group content solo and so far I've only been doing missions to level (I'm just level 18). They also added a bunch of the paywalled options in the character creator for free, and unlocked access to the content that was behind max characters (like the alien races you could only start to play if you had a level 50). Of course City of Villains is also included, and it's all completely FREE.
NCSoft backs this game project now, and there's even been free updates from some of the devs.
I'm on the Victory server but I only see a few low level noobs in Atlas Park / Galaxy City, as soon as I went into higher level zones like Skyway City or Steel Canyon, it felt like a single player game. I don't mind personally, I even did a taskforce by myself as a tank, but there doesn't seem to be many players online.