I'm in full support of an official parser simply because of the potential good it can bring, and also because it'd be much, MUCH easier to discern if someone is actually abusing parsers to harass people, because the plausible deniability is no longer there.
I find most of the fears of parsers being abused come from anecdotal stories from the community's interactions with hardcore raiders, when it's an established fact that the vast majority of people using parsers are within that community, and it's also a given that such people are also FAR more likely to have a certain attitude. Open it up to the rest of the community, and the abuse from the elitists will basically be diluted out.
The potential for it to be a force for good is too important to pass up. Astrologians can easily judge who can make the most use out of their cards. Actual mentors would be able to give advice to players of the same class, and the mentees (assuming they are actually willing to learn) would be able to IMMEDIATELY see how much they improve by following the advice. The reverse is also true - everyone would be able to immediately notice if the advice being given out is straight up bad.
Of course, willingness to learn is a huge part of it. People who are unwilling to learn will always be unwilling to learn. But we all know it's not okay to behave like that, just like it's not okay for an elitist to suddenly boot someone decent out because they only did 10% less damage compared to their best friend. But this is for everyone else who WANTS to get better but doesn't know how to, due to a combination of having no reliable mentor to guide their progress, and not wanting to resort to using third party programs that are considered taboo by much of the community (and using a PS3, in which using third party programs is out of the question anyway).
Don't hold back the rest of the community because of the concerns over the two extreme sides of the spectrum.