Expansion Idea
Some initial problems:
Creating the skeletons for new monsters is a lot of work. Even now, five years into the game, we still don't have so much as stray cats and dogs roaming the city.
How does this tie in to the superhero genre? There are plenty of games in which players control fantasy heroes, including beast tamers or monstrous warriors. What grounds this in City of Heroes?
You say this is after "all the bugs have been fixed." But that isn't something likely ever to happen. With any constantly-evolving game like an MMO, there will always be more bugs.
Would these characters be able to participate in PvP? It sounds from the description like you're talking about RvR combat (Realm vs Realm); when you say these characters are more powerful than most heroes and villains, why would anyone ever bother trying to fight them?
Why do these monster characters deserve their own archetypes, much less faction? There are plenty of monster-like heroes and villains.

[ QUOTE ]
With any program, there will always be more bugs.
[/ QUOTE ]fix't
"The program is finished when the programmers are done putting all the bugs in."
http://www.fimfiction.net/story/36641/My-Little-Exalt
Eh. Static programs with clear goals and finite length and complexity can be fully debugged. It's just, the effort to do so rises linearly as length increases, and multiplicatively as complexity does... and you may need to build a dedicated machine and OS to run the final product on.
But my "Hello World!" runs great!

I was a bit tired last night, and like I said, this is VERY far fetched, but in the end, its just an idea.
The Idea, you build a monster, instead of a hero or villain. Something that is enemy to both sides. They would have their own area, but one major aspect would be total pvp. They are monsters, with no "sides". In their own zones, only small places would be non-pvp. When they grow in levels, they have the ability to choose to raid a zone, occording to their level. This is where being more powerful comes into play. You could litterally have a small or large team of other beasts, with ALL of atlas park taking a swing of you.
Also, the character creation? You have something like "huge" body type build, but with the ability to make it 9-10 feet tall. Thats tall enough to make it so it isn't GM size, but enough to say, "Oh, look, a monster".
They wouldn't be push overs, so I would think the ratio to take one of them down would be something like a 2 hero to 1 monster ratio.
Again, this is just me sharing an idea that popped into my head. I don't expect even a dev to look at it. Just wanted to see what all you think.
Also about the bugs, what I ment was, "When all the bugs are fixed UP TO DATE." I know of course when you add new content, you get more bugs.
Like I said, this would be an expansion. They really don't need their own archtypes, but it would be something cool.

50's (Only most important)
Zuraq (53 EM/SR Brute)
Stagmalite (50 Granite/Fire TanK)
(Couple of other's I don't care about.)
It sounds like what you want more is the event -- a player-driven RvR -- than the actual power sets.
If that's the case, what about something like a special zone or Arena type, in which one or a handful of players got to build and control large monsters and everyone else in the zone/arena tried to kill them? Maybe you could unlock Monster Powers the same way Gladiators are unlocked now.
(There would probably have to be some incentive for people to want to play regular characters in that match -- maybe beating a Monster awards everyone on the team that takes it down a slightly higher than normal chance for a PvP recipe or something.)

If this is suggesting anything even close to open PvP, I'm against it. Forcing PvP on anyone is not something I think would work well for the game.
If it's something more like a heavily modified zone or arena PvP system, I'd be all for it. Seems kind of interesting. Maybe akin to getting the RV heavies.
As an expansion on its own, I don't really support it. Seems to be a weird and highly specialized way to create a character.
I know of how many bugs that need fixing, I also know this idea is very far-fetched, but again it is just an idea.
I also did a search beforehand, but found nothing similar, so my apologies if this has been mentioned.
My far off idea, after all the bugs have been fixed...an expansion. Optional.
The expansion? Eden's Beasts (Name needs work, but it is better then "City of Monsters" or land of monsters.)
In this expansion, you get to split off from both the heroic or viilainous role. You are an enemy to both sides. You have the ability to create a beast or monster. Something powerful, but not GM powerful.
How would this work? New Archtypes, (not entirely new, a mix of exsisting and some new ones.) Common raids of both "cities" much like invasions.
How would you survive? You would be more powerful then the average superbeing, yet not unstoppable.
An example of an new archtype.
"Destroyer"
Primary Blast, secondary defense. (Blast/Tank hybrid)
Special (No name, but sort of like a fury bar)
"You are strong, even heroes tremble in your wake. But all this power comes at a cost. You are slow, and if you dont spend your energy, you slowly lose health. If you begin to destroy, your mind wanders and you lose sight of your defenses as your attack grows."
Basic idea, and I am tired, still more info to be put in. Will post more tommarow.
First Thoughts? Suggestions?
50's (Only most important)
Zuraq (53 EM/SR Brute)
Stagmalite (50 Granite/Fire TanK)
(Couple of other's I don't care about.)