I'm skeptical. In fact I'd go so far as to say I doubt it'd work at all. It's an awesome idea and you've done well to think of it, though it requires the prerequisite that the person with one-itis is thinking logically, which they are not.
One-itis, in psychological terms, is 'limerance'; it's worth checking this out and evaluating the research before forming an opinion on one-itis.
I think it's easy to ask someone to do that and think they'll be able to accomplish the task appropriately, but I simply echo RockyD; you wouldn't be able to do it properly. If anything, it would just get you thinking more about the girl, and then you'd realize how much you love her all over again.
The point is those with one-itis
can't focus on the girl's negatives. They either don't see them, or they don't even
want to see them.
My opinion is that as a community we try to prognose and 'fix' one-itis too much, as if it were some sort of disease. You can't. Just let it be. Let it play out. Only time can 'heal' it, if you consider it an ailment.
No matter how many amazing techniques you get from the community, and how much you know, once you're in one-itis, this all goes out the window.
If you ever know someone with one-itis (which I'm sure you will at some point) in the near future, try to get them to do this, I bet you it won't work and will probably make it worse.
I had a small case of one-itis a few weeks ago now, and I'm only just recovering - that's pretty good time, but then I only interacted with her for 30 mins

. Thinking of using your technique, I don't want to think of it any further, because I don't even want to think of her - but maybe that's just me!
One-itis can get anyone, 'guru' or 'afc'. Anyone, anytime. I say just let it be and if you get the girl, great, if you don't, just keep breathing and give it time. Anything that requires you to 'try' to fix it, will probably by the very nature of 'trying' make it worse.
Just adding to this, how many times have you heard someone with one-itis say, "but she's perfect" or "I'll never find anyone else like this". Hell, that's what I still think about my one-itis!!!! My head knows its not true, but I can't FEEL it's not true. If you think she's perfect, how are you going to list negative qualities about her? You'll just end up listing more positive ones and then realising how the positives outweigh the negatives to such an extent that you end up reaffirming your one-itis.
I'd end by saying that for me, Mystery's (I think?) idea of going out and sarging bare is still the best method for helping one-itis on its way out your ass. That shit works, it's just getting the person to do it and get in the mood to sarge well.