My opinions:
We have settled on the idea of the 'standard' metagame. We aim it to be well balanced and have other desirable features, while also being quite 'inclusive'.
In this metagame (and in any) some Pokemon get used more than others. I believe there are two reasons that a Pokemon gets used a lot. Firstly, a Pokemon can excel in one role. Secondly, a Pokemon can have versatility, being good in many roles and fitting well on many teams.
Conversely, a little used Pokemon might be little used because it's lousy, but it also might be little used because it's a niche Pokemon. The former probably should not be used in serious standard play, while the latter most definitely should see usage in standard - but not a lot of it, hence their not being OU.
(In practice, for most Pokemon a mixture of both these factors applies. Think of them as like endmembers.)
In WiFi, there are also practical considerations. A legitimate WishBliss is very hard to come by, while a much more readily obtained Wishfable can fill a similar role quite well.
Ultimately, you should choose what you think are the best Pokemon for your team. If that means running Pory2 to check a wide variety of threat, or running Clefable as a supporter, or Regice alongside Blissey, or whatever, then don't be scared off it because those Pokemon are rarely used.
We have settled on the idea of the 'standard' metagame. We aim it to be well balanced and have other desirable features, while also being quite 'inclusive'.
In this metagame (and in any) some Pokemon get used more than others. I believe there are two reasons that a Pokemon gets used a lot. Firstly, a Pokemon can excel in one role. Secondly, a Pokemon can have versatility, being good in many roles and fitting well on many teams.
Conversely, a little used Pokemon might be little used because it's lousy, but it also might be little used because it's a niche Pokemon. The former probably should not be used in serious standard play, while the latter most definitely should see usage in standard - but not a lot of it, hence their not being OU.
(In practice, for most Pokemon a mixture of both these factors applies. Think of them as like endmembers.)
In WiFi, there are also practical considerations. A legitimate WishBliss is very hard to come by, while a much more readily obtained Wishfable can fill a similar role quite well.
Ultimately, you should choose what you think are the best Pokemon for your team. If that means running Pory2 to check a wide variety of threat, or running Clefable as a supporter, or Regice alongside Blissey, or whatever, then don't be scared off it because those Pokemon are rarely used.