Thanks, voxanimus, I really like your comments on "athleticism" and your examples.
Here are some random thoughts/observations.
First, tho, I actually think it's possible to trace the development of this stuff (e.g. rumaals, athleticism) to a pretty good degree. Sure, things evolve organically to a certain extent, but you also have a lot of individuals who introduced certain things, which were then imitated (consciously or unconsciously), etc. And there's probably enough media from recent years that one could look at it and trace a lot of stuff pretty well (even if not precisely). That is, if anyone cares to. I understand why they wouldn't. And I'll admit that the last several posts I made in this thread have been mainly to amass sources of data in some rough organization, without "analyzing" it closely.
So my observations are a bit casual.
One is that I was surprised how much MIT's style, even in the late 90s, reflected a lot of Indian bhangra style. This was at a time when "most" other North American groups looked quite different. Although I have not seen all the groups -- I am sure there were maybe others that looked similar to MIT, too. (And here I am not including the "exhibitional" groups like SIAC and Punjabi Lok Virsa, which I think belong to a sort of different scene and which at that time had not influenced the style of bhangra overall.) So I wonder, for example, what sort of channels of information informed MIT, e.g. visits to India, certain guiding figures, whatever.
Incidentally, I had a chance to hang out with some of the people from the MIT team (friends of friends) back in 2002 (2001?), and even accompanied them on dhol for a performance at a wedding. (There is a funny story that goes with it, where in the course of 2 days, I broke the dagga skins on both the dhols they loaned me -- one during the performance.) Anyway, I had earlier done some stuff with the UC Santa Barbara "team," which looked odd to me after studying in India, but then came to look like what I would consider pretty typical for most "non-elite" groups at the time. And MIT did not then strike me as anything except, perhaps, a bit "better informed." I certainly did not have the perspective at the time to think that maybe MIT knew more about Indian bhangra style than most American groups. It still looked like "American bhangra."
Another anecdote. In India in 2001 I was in a workshop where Garib Dass and one of the dancers from "Learn Bhangra in 7 Days" were teaching a group of international participants. Some of the American non-Punjabis were executing the moves (newly learned) in a kind of style that might go with the Black popular music they were used to dancing. Others were dancing kind of "jerky," in a way that most American bhangra groups in the UC Santa Barbara vein would do. (I want to note that when I describe any of these styles I'm not putting them down. "Jerky," for instance, is just a way that works to describe it.) And then of course the coach and Garib Dass were dancing in their 1970s-1980s Indian bhangra style, which was not the super fluid style of the 50s, and yet was quite 'light" and "graceful" (vague term, I know), and not "aggressive." All these styles seemed to make sense based on the background of the individual dancers. What was actually most striking, tho, was the style of one American-born college-going Sikh Punjabi participant. He executed a lot of the moves with familiarity -- probably had already done them in college settings in the U.S. -- but in a style that was totally different than everyone else. He made huge, broad gestures. They were very deliberate, as if practiced and believed to be a proper way. Of course, this was a style that many people were doing in America then, though I'm not sure for exactly how many years (less than 10, I'm sure.) The style was so deliberate and seemed so well established, and yet it different so clearly from what the local Indian bhangra coach was doing.
The way this Punjabi-American college student was dancing in 2001 seems clearly to have been something developed in the 1990s in America, and I think we could probably narrow it down to certain teams (or certain areas say, East Coast or whatever) that had started towards that end.
Another random anecdote. I'll always remember the comment made to me by a Punjabi-American friend in the early 2000s, when speaking about how they didn't really enjoy watching bhangra competitions, etc., although this person was a great fan of Punjabi movies, music, etc. They said that the style of dancing looked like the dancers "wanted to kill you." They were speaking to relatively recent bhangra.
Yet another comment, though it is uninformed and not worth much. This is a comment of a non-Punjabi female friend of mine in 2010 who didn't know anything about bhangra but who had seen several performances in the course of dating a Pakistani Punjabi man. I mentioned bhangra to her and she just started laughing, saying that looks so "gay" (as in homosexual).
The look of traditional Punjabi dances is certainly more "feminine" than anything people are doing today in North American bhangra. As discussed before elsewhere, that dimension related to an aesthetic style, concepts of grace, etc., that don't have any clear relationship to actual "masculinity." Male ballet dancers, for instance, are totally "masculine," despite what ignoramuses might perceive as looking "gay." And I always remember the description of the PEPSU bhangra troupe from the 1950s, which was said to enthrall female onlookers by being both "feminine" and "masculine" from one moment to the next. And yet in the world of traditional Punjabi performance, dancers were a different sort of animal, and the professional ones were expected to have a more "feminine" grace. There was no shame in that -- at least not for them. There may have been shame for the lay people (Jatts, etc) who frowned on dancing. The PEPSU troupe, although led by such "laypeople," adopted the graceful style associated with professional dance. Rumaals (and ghungroos!), it seems, went with that.
On a tangent about rumaals: It seems like the PEPSU troupe used them, and they were the ones who set the mold. Following groups did the same, as did film images of bhangra. They were used 1950s-60s in India, perhaps disappearing among most in the 1970s. The few Punjabi "heritage society" groups (Vancouver, Bay Area) had a basis in dance of the 1960s, and so they continued the rumaal thing. My guess is that they passed it on to the North America college groups of the 1990s.
Given that there is no natural correlation between the masculinity of the dancers and the style of dance, I hesitate to make any conclusion on why recent groups ditched the rumaals and took on, first the "I'm gonna kill you" and then the athletic style. I mean, if the latter styles were supposed to look more "tough" and masculine, it obviously didn't work in the eyes of the non-Punjabi woman I cited. However, I do suspect that there was some shift in style based on how American bhangra dancers viewed how they should look, and in an effort to make it more "tough" looking. That these dancers were not informed about how dance looked in India, or that flowy-gracefulness is no less tough, is besides the point. It seems like a way of moving the body was being established in American bhangra before the "traditional turn," and I can only guess it was based in somewhat misguided ideas about what it meant to move like a Punjabi -- you know, those people with black hummers and Sinbad beards who can drink gallons more of booze than the wimpy little Madrasis that -- God forbid -- someone might confuse them with (<<sarcasm!)