What do you think defines an overpowered Pokemon?

Or do you think a Pokemon cannot be overpowered? What characteristics makes a "broken" Pokemon? Should a broken Pokemon not require support from its team to be successful (there are possible exceptions of course), and should that be one of the reasons why it's broken? Do you think a Pokemon that "centralizes" (or comes close to it) the metagame makes it overpowered, or do you think it's natural for a metagame to adapt to a certain Pokemon? i.e. Certain Pokemon using Hidden Power Fire exclusively for Ferrothorn. Do you think overpowered Pokemon should be banned?

Do you agree with Smogon's definition of an overpowered Pokemon?

Offensive Characteristic
A Pokémon is uber if, in common battle conditions, it is capable of sweeping through a significant portion of teams in the metagame with little effort.

Defensive Characteristic
A Pokémon is uber if, in common battle conditions, it is able to wall and stall out a significant portion of the metagame.

Support Characteristic
A Pokémon is uber if, in common battle conditions, it can consistently set up a situation in which it makes it substantially easier for other pokemon to sweep.

Click to expand...

(Keep in mind that this was intended for generation four; they likely do not follow this anymore.)

I think a pokemon is considered broken when it centralizes. Obviously the idea of centralization requires a definition because it varies from person to person and is very...vague. Essentially I see the word as meaning you need a specific pokemon on your team to counter said pokemon, or require a specific set on a pokemon to stop it. Examples of this are things like SpD Jirachi or (like you said) HP Fire on certain pokemon to stop stuff like Ferrothorn. It's just annoying. Sure, checking specific pokemon is important, but if you have to do something ridiculously unconventional just because of one pokemon, that's a problem.

That being said, I don't think there are THAT many pokemon that are centralizing. Sure the HP Fire thing on ferrothorn could be an argument, but what's stopping you from using something else to deal with ferrothorn while checking other stuff too?

I believe .Aero is most definitely spot on ^ _ ^

However I don't believe "countering ferrothorn" warrants running hp fire if ferrothorns was lets say normal-type just for the sake of an example there wont be a rise in hidden power fighting being used by pokemon :L when I think of countering ferrothorn what pops into my head is countering "hazards" not the actual ferrothorn because if it didnt get stealth rocks or spikes it wouldnt be able to do much else? and if it didn't have those moves I firmly believe it would drop to UU and face competition from bronzong :/ ferrothorn is most commonly run on rain teams and an un-stabed hp fire will not do much.

Anyway I'm gone completely off the point here :P

Offensive Characteristic
A Pokémon is uber if, in common battle conditions, it is capable of sweeping through a significant portion of teams in the metagame with little effort.
I know you said they applied to gen IV but its still partially true.
Sun is common(ish) that would make Venasaur uber, using .Aeros well made point most teams have to have an answer to venasaur in the sun or its a win condition for your opponent really :/
When considering my point imagine if chloropyll venasaur and drought ninetales existed in Gen IV there were less potent revenge killers and pokemon with base stats over 135 in offense didn't exist even with the old growth mechanics this would be broken :L

I guess with the evolution of competitive battling the better the pokemon get the cut off point for "uber" grows much higher. and the definition of "overpowered" is very...vague.(Thanks .Aero xD ) kind of like the wind(yes I love metaphors) you can't see it or guage it completely accurately with just your own senses, but it has to lift houses and cars off the ground before its considered a hurricane(Tornadus-T reference I'm on fire ^ _ ^)

Smogon's definition isn't bad but it uses the phrase "common battle conditions" without specifying in what tier.

Also:

Should a broken Pokemon not require support from its team to be successful (there are possible exceptions of course), and should that be one of the reasons why it's broken?

Team support is always important. There are pokemon that are successful mainly because of the combinations they can utilize. Excadrill with Sandstorm comes to mind (just an example).

I think that if a Pokemon has great stats, and a good moveset to take advantage of those stats, plus there ability will help it do its job (sweeper, wall, etc), then a pokemon is overpowered.