I believe! All non-believers will be...eh...FORCED TO BELIEVE!! OK not really. But most people-Even people who prefer other pairings- believe that NaruSaku is definately the most plausible(I know some people who like NaruHina.Now only if I could get them to see the light...).
I could sorta see Naruto with someone else, but unless Kishimoto is somehow tortured and forced to change, I doubt it'll happen. And usually I'm the one that prefers the odd pairings...
The main problem is that most authors don't know how to use OCs well. Sometimes really-powerful OCs aern't too bad, but there has to be some sort of conflict, some development, some flaws.
Sometimes introducing an OC can be a problem too. If you introduce them by making them "save" some main character, some people just mark it off as an over-powerful OC. It could probably be pulled off though, but it depends.