Even though Chun was strong in S1, the players who were good had to play a solid game. It is not like she can out guess you out of a set, even with V-Trigger her damage conversions are pretty tame imo. I think she actually was fine in S1, she felt like a complete character (tbh it felt like more that the lower tiered characters were gimped than the top being too strong), effective in multiple ranges. IAL give her a reason to leave the ground, and people were getting used to AA it, with jabs, and some character could get a stronger normal to AA it. Speaking about her AA, but I don't think the st.lk AA was as bad as people complained about it. It was effective and quick, and gives her the momentum to dash up afterwords, but it seemed like other characters like Cammy or Necalli can easily have their rewards outweigh the risk of getting AA by a light normal.