Meta-gaming means using information the player has and the character doesn't to the advantage of the character. The line between what you know and your character know is often somewhat blurry, especially in RP'ing where there are time gaps between your posts. It is not always abuse, it is sometimes something that happens without you even realising it.

For the rest of your post I'm just going to quote Brovo;
[quote] two people with the same archetype you can set up such classic relationships as apprentice-mentor or comrade-comrade, battle brothers, rivalry...[/quote]
That was it.

Besides, let's not forget that two people rarely write the same character the same. Superhero comics are a prime example of this. The CS will essentially be void as a descriptor as soon as the IC starts and we get to the show don't tell part of it all.

As for RP's requiring specially assigned roles; Have fun that one week before it dies because one person dropped and you need to put everything on hold to find replacement. That's a flawed set-up to begin with.