Near sunset someone (I believe it was Arcanaville?) made an extensive and well-thought out post supporting just that.
CoH is a case of terrible game design and failed decisions, that somehow magically "worked great" in the end. Resulting a game that defies expectations, sets new precedent and will never be replicated again due to this.
A good example off the top of my head to support this thesis;
People praise this game for the lack of the "holy trifecta". When in fact, the devs originally intended for there to be such a thing. They just messed up balancing so badly that the holy trio was not needed for the bulk of content. Scrappers could do well enough on their own that they didn't need a tank. Tanks could do enough damage that they didn't need a Scrapper. Lengthy, binary holds are a nightmarish idea balance wise, same with overwhelming and stack-able buffs/debuffs. But somehow it all just "works"
The single most important event in the history of the game was an event no player saw. The original design of the game included the notion of the holy trinity, which at its heart is the fundamental principle of MMO teaming: make every archetype "necessary." At some point, and even I don't know when it happened exactly, and maybe it happened unconsciously at first, the fundamental design principle of CoH became "everyone should be able to solo."
The idea that everyone should be able to solo in an MMO was not just novel, it was downright heretical at the time, and is still a wild idea for most MMOs that aren't shooter-looter type games. But in City of Heroes it opened the door to everyone being "overpowered" in an MMO sense, which just happened to match the concept of the game being about superheroes.
City of Heroes is a broken, twisted, cobbled together thing in which half the stuff doesn't really work and half of that can never really work. But what's left targets a very specific gameplay style no other MMO serves, and no other MMO can serve. Being super-powerful in a world of super-powerful things.