I avoid online Wii games precisely because of the friend code system. Mario Kart Wii is the exception, but that's because the multiplayer works so wonderfully. Smash Bros. Brawl online is a shot in the dark and fails more often than it works. So I don't play it online.
I'll say this, though: The PSN is the way to go. It's free, it has system-specific codes, it tells you when people are online and when they get offline, it tells you what game they're playing, and it tells you if you've been invited to a game.
The trash-talking argument is silly. Just implement an option where you can mute particularly irritating individuals (like every other company does) and you're good.