In my opinion, AoS was just pouring salt on the wound, adding insult to injury, etc. Publish 16 set the stage for what was to come, a game geared more toward item collecting and creating imbalance. One that was geared more towards the current playerbase rather than appealing to new players.
Champ spawns themselves weren't a bad addition it was the scrolls. However, I could live with power scrolls in a classic shard (though my preference would be to not include them and set some of the skills to what they once were before pub16). Yes, AoS was the killer, but Pub 16 got the ball rolling.