Can't really say I'm surprised that game has shut down... I've never played it but when I saw that CoV was merged into CoH, I kinda knew that the game was going to shut down eventually.
You also need to take into account that there have been several MMOs that have been released sicne CoH was brought live... like Tera and Aion and I've haven't seen a retail box copy of CoH in a long time.
Worse comes to worse, it'll just end up being F2P like LOTRO and Age of Conan.
CoV and CoH were merged on purpose so Heroes, and Villains could fight against each other in new PvP zones, or RP, or whatever.
Also. CoH went to a F2P/subscription hybrid last year, and was doing quite well with new powersets, and new free(for subscribers) content coming out every few months.
I played that game for over 6 years, starting in October 2004, and only recently took some time off(I still played once a month for Tanker Tuesdays) to try other games( WoW, DDO, Champions, DCUO) because I had done everything in it. I planned on going back in January to try all the new Incarnate stuff, and new powersets, but that's not gonna happen now.
I'll have to settle for Champions Online(also by Cryptic), which has a great character creator, just like CoH, but not the great team play, Villains, stories, or mission creator like AE(why hasn't Cryptic brought Forge over from STO yet?!!) to get my non-holy trinity superhero fix. I do love that you can pick up, and throw things(cars,lampposts, etc.) at villains.
DCUO had beautiful graphics, and some interesting missions(at least the first time I played them), but it's customization, powerset choices, and mouse-clicking overuse while not having a cursor to click on things left alot to be desired.
It would be so awesome if Blizzard, or anybody could purchase CoH, and keep it going.