The crazy thing about this Oprah interview is how it will be perceived by her viewers.
The majority of Oprah's US viewers are housewives/mothers - some 50-odd million people. And the vast majority of them have one thing in common - a disinterest in or lack of knowledge of in sport or cycling and Armstrong in particular. Most would have barely a passing knowledge of who he is. That there is his weapon in this interview. He's going to gain tons of new supporters.
While the people who know about him and have followed this saga for years will be generally galvanised in their lack of sympathy of any admission of drug taking, the classic Oprah audience will lap up his admissions and humility (real or staged), his explanations of the huge pressure of trying to be good role model, his motivation to reward all the people who supported his fight with cancers etc etc.
The people who dislike him will continue - if only short-term until they get over it but the classic Oprah crowd will love him - they always love flawed celebs who come out, show some humility, say they're sorry and have a little cry with 'mother of the nation'.
Basically, he can take a flying leap as far as I'm concerned. Until he fronts up and apologises in-person to the people's whose careers he destroyed with lies and personal (or financial) attacks - people who often worked for/with him and were actually offering a helping hand when confronting him about the PEDs use - he should be sued into oblivion. His decades-long ruse warrants jail time for a number of events and I hope the authorities take his appearance on Oprah's show as nothing other than gathering evidence for future action against him.