I played Champions a little to get my costuming fix. If you turn off the cel shading it doesn't look so hokey, and it's certainly more fun that it was when it first came out, but no, still not CoH.
And I'm a huge Star Trek nerd, so I enjoy STO, but it's an entirely different kind of game really, so no.
The one game that I have played that has given me that same feeling of awesome that CoH did, is Secret World Legends. It's a beast to download, but even my 10 year old rig could run it, if not well. It's also mature content, and a bit of gore, but if that doesn't bother you, I highly suggest it. The writing is fantastic and some of the things they did in missions are unlike anything I had ever seen. It's free to play, but there's a few perks for people who sub. Character creation is a bit limited, but once you're in game you can unlock more clothing options, and like CoH, you can wear whatever you want independently of your gear. And the community there is almost as nice as this one.
Oh, and have you checked out Paragon Chat? Or just the costume creator? It's still not the same as having the full game. But it really is cool to get to visit all the old places and hunt badges. And the holiday events are pretty fun at Halloween and Christmas. It's also great for RP and just finding some folks to commiserate with.