Here's what I think.
If you transplanted Michelle with the skills she had in her late teens/early 20s to today and gave her elements and choreography based on today's rules, she would do just fine. I'd expect level 4 spirals with +2 GOE, and spins and steps at levels 2-4 often +1 GOE. Also she'd get a lot of +1s and even 2s on her jumps, and she would get high component scores. I don't think she would win everything in sight, but I think she would be a consistent medal contender.
If you go back and score her actual programs from those days, she didn't have all the higher level elements because they weren't constructed according to rules that hadn't yet been written, although they often did come closer than what many of her competitors were doing. (For example, she would get credit for her spiral sequence because she did hold at least one position for >3 seconds, whereas most of the other skaters at the time just hit each position and moved on to the next.)
If Michelle in her late 20s were to return to competition, she probably wouldn't do as well as she would have with a younger body just because of the toll that the years of pounding have already taken. Also it's harder to develop flexibility as an adult than as a child or teenager; my understanding was that trying to learn new flexibility moves in 2005 was part of what led to her being unable to compete in 2006.
If extreme back-flexibility moves had been rewarded as heavily 10-15 years ago as they are now, I'm sure she would have developed more of them but, that wouldn't have been her forte. Instead, maybe she'd have used the opposite-direction spins more often and would have popularized that spin feature as well as the change of edge spiral.
