The things I liked the most about City of Heroes.
1. I could play MY way, I could solo if I wanted to, I could team if I wanted to. I could drop the difficulty down if I wanted to or turn it up if I wanted to. I could street sweep if I wanted to or do missions if I wanted to.
2.I felt like my characters where really mine. I made them from scratch, I choose every detail about them. Their name, their clothes, their origin, their powers. How their powers looked and some times how they animated.
3.I felt like I was really a super heroe, walking into a room of +4x8 mobs and being able to beat them solo. Who wouldn't feel powerful after that?
4. No Holy Trinity, I liked that I didn't have to worry about wither or not my character. Fit into the Tank/DPS/Healer mold. My character (as with the case of my bots/dark MM) could be alittle of both. He could tank (I took taunt in a power pool), DPS (with his bots), heal and do alittle crowd control too.
5. They had more than one pet class and they kinda scaled if you think about it. Doms and controllers for the people that wanted pets but didn't want to micro manage them. THEN MASTER MINDS (my favorite), you could micro manage as much or as little as you wanted with them. Master minds in my oppion should be the stander for all pet classes for all MMOs ever. You had as much control over your pets as you wanted.
6. The gear grind (or in this case IO grind), you didn't need them. You could play your character (before incarnates, which you didn't even have to become an incarnate) with out IO sets forever. So you could choose how much or how little you would grind for IOs.