Several things I miss about COH:
1. My super group that I helped head. While most of us are real life friends (and I'm certainly still in touch with my girlfriend!), and I'm still in touch with my co-founder through Marvel Heroes, there's something to be said for that sense of togetherness where, no matter what characters you go in as, you know everyone else has your back, you have his/hers, and you know how everyone will act and react. We were TIGHT.
2. The welcoming chatter and community. I could log in and, regardless of zone, likely hit up someone to chat with, happily and freely, buddy or not, through a chat channel or in zone local or broadcast speak. In so many other games, this is missing; I log in, try to start up a conversation or just shout out a "Hi folks!" to the zone, and I get nothing in response.
3. Sights and sounds and music and power activations: stuff that made the game alive. Knowing that when I hit that "Bow-chicka-wow" music of Blyde Square in Steel Canyon, I was near the base portal. Getting a kick out of teleporting into a crowd with Waddle the Penguin and Glacier freezing everyone around me or tripping them up with an ice slick. Shoot, even watching that flaming fists effect on Hasten, even if it didn't really fit all of my characters but still finding it very cool.
4. The Architect Entertainment system. I teach English. I love to write. I've been role-playing for about 25 years, being self-taught on Dungeons & Dragons in the 80s. The AE system was a wonderful blend of tools (though buggy!) that let me see, in the end, eight polished tales to final stages and to connect four of them into an ongoing arc for developing a favorite character.
5. Finally, the ability to just log in for ten or fifteen minutes, run a radio mission or AE blitz one of my arcs, craft some stuff in the base, talk to some friends at two in the morning, or just hang in Atlas Park and hold a costume contest on Justice. . . . City was a game where you could have a great time commitment, like running numerous Dark Astoria incarnate missions in a row or getting in a Rikti mothership raid, or you could chill out for a quarter of an hour and still feel fulfilled. So many games require BIG time investments to get much of anywhere, particularly late game, but even as a level 50 incarnate, I could simply mess around or run a hero tip mish or whatever without needing to have an "epic story" all the time. I really miss this, perhaps the most.
I hope that NCSoft reopens or sells the game; should they do either, I hope they have the capability and willingness to set us back up with all our old stuff. I know that might not be physically possible and that all our characters and stories might be long gone due to a simple "format c:\, enter". . . but there's always hope, until we hear otherwise, right?