Well, look at it this way. It took a dev team however many years to create the first iteration of city of heroes.
After that, it was improved on and made increasingly complex over the course of eight years.
To answer that question, I'd point at CityOfTitans. They've been at that for years and it's still not out the door.
Even if you ignore the possible connotations of mismanagement and bad directions at having switched engines, the answer is still it would take years to develop.
The only way to change that is to throw more manpower at the project which in turn requires more money.
If it were me? I'd throw my chips in with SEGS. That project has been around for a while though it's finally making progress again.
The only thing is it's all free work. I mean as a software engineer, if I was out of a job I'd put in some time there to help.
But you know how life is. It's hard to stare at a screen for eight hours, go home, and stare at it for another four. Only this time without pay.
Also there's the possibility of having your butt sued off by NCSoft. I wouldn't put it past them to try to get greedy and defend their assets.