Being better than half the cast makes you middle tier. Winning lots of tournaments... Doesn't define a spot. And how many, exactly? Which ones? Statistical voting also doesn't make someone top tier.
Oh yeah, Smogon tiers run entirely on usage. The eventhubs higher-ups admit that their tier lists can get clogged with popularity sometimes (Bowser 44th, SHulk 1st), and they are extremely erratic, in one day Shulk got every ranking twice at least..
tl;dr None of those make you top tier, and where is the proof of said feats?
So let me bring my side of the story: As good as Rosalina is, people have gotten used to her. Luma, is great. Really great. But even if Rosalina is still usable without it, she's still quite handicapped. She's extremely light and dies quickly, and while her gimp game is great, she can struggle to kill heavyweights, because after a matter of being touched a few times you're in danger of dying from the next hit sustained. She has stage contorl, but people as far as I've seen are finding ways around it. Rosalina is like that huge threat that people slowly get used to, as unlike other top tiers, things aren't being found for her constantly to leave us unprepared. While she's won quite a many tournaments, a majority of them were before 1.0.4 and many people don't like using her in tourneys because it means a campy playstyle.
Don't get me wrong, I think she's still top 10. She has a personal shield, ridiculous recovery, good hitboxes, extremely annoying ways to get past you, and can usually get free smahses in. But I think the criteria for 2nd or 3rd place is strict, and that she barely doesn't meet that criteria. I'd put her in Top 10, no lower, maybe even top 5.