Thanks for your post man,
BTW, I'm sorry to hear about your situation. I myself have only 2 invites (from places I didn't rotate at). Step 1: 233 Step 2: 247. A's 3rd yrs, top 40% of the class. I've been wondering the same as you myself.
From what I understand from attendings and residents a research year is the most beneficial if you can build a strong relationship with the dept to significantly increase your chances of matching there. It seems like its less about going to a big name place where you are just another researcher and more about a chair, PD, faculty, etc saying "I've known this guy for a year, he's a hard worker, great guy, a thinker and I think he'd be a great resident", even if that means its a smaller program. If you think about it, you technically only need 1 place to really really like you to match. But again, that may have been just what I was told.
BTW, is it too much bad luck if maybe we start a post about some of us that are "less fortunate" as far as interviews so far? While its great that people are getting such amazing interviews, its so hard to gauge whether this is representative of the general cohort this year. I know there are a thousand factors (scores, AOA, papers, who is a member of orthogate, etc) to skew data...I dunno, I guess I was just thinking of something to maybe boost (or drop) morale.
Continued good luck to you and everyone else!