I say let the Furlings remain ambiguous. I think it's hilarious they have been mentioned once, (well twice in 200 but that doesn't count) then *ZAP* never again.
As for O'Neill centric, he has to be in it, but the show evolved to be about the team more then any one character. Feasibly, if the storyline centres on O'Neill, the majority of people will be happy. However, keep the other guys in focus, cos they're alright, yeah they're allllllright.