An interesting thing to wonder is which previous years of the decade prior would Jill Trenary have been able to win with her 1990 Worlds performances.
Here would be my take:
1980- Under 1980 scoring hard to say. I am pretty sure Poetzsch was much better than Jill in figures. Poetzsch and Fratianne both did double-double combinations like Jill in the short I think. In the long Poetzsch was rather weak, so Jill would have easily outpointed her there. Would she have been able to catch up to Poetzsch's figures lead to win?
1981- I dont think she would have beaten Denise here.
1982- This years was a mess, she probably had a good shot to win this year with her 1990 performances.
1983- I doubt she wins this year. Sumners at her peak was probably better at figures, and Jill's short program in 1990 was much worse than Sumners in 83 which only placed 4th in the short.
1984 Olympics or Worlds- I doubt she beats Witt. She never beat Witt at figures when they competed head to head, and Jill's short program from the 1990 Worlds would place really low in the fields this year.
1985 Worlds- definitely no.
1986 Worlds- definitely no.
1987 Worlds- definitely no.
1988 Worlds- Same comments as 1984.
1989 Worlds- She wouldnt have won in 1989 even with her 1990 long program, despite a much better short program in 89 than 1990.
So I think 1980 and 1982 are the only years really she would have won with her 1990 winning performances.