^^-- It seemed to me the problem was more the weatherman, or the lack of rain. They'd forecast it almost all the time, but when they forecast chance of rain over the next three days and it pours the first, usually the chance goes away for awhile. They'd just keep forecasting it and it wouldn't happen.
My impression was that 2009 was a very dead year, I'd see almost no one enough visits in a row that I was actually concerned for the park. While I305 didn't exactly pack them in, its draw really didn't peak until maybe 2013-2014. 2016 seemed to me to be going the way of 2009, not that bad but I didn't go as often on weeknights in June so it could have been. 2017 (EDIT: 2018) would have been a stronger year except Volcano went down before a lot of people got around to checking out Timbers. But it could have been a bad one if it weren't for the addition.
Of course, I'm the last one to complain about lack of crowds, as long as somehow the park survives and stays great. But there have a been a few times it seems too good to be true. RE: "Dorney South", actually I think Dorney got bigger crowds this year than usual. They actually had to turn people away one Grand Carnivale night, and there was another report of crowds after that. Queue-times also reported long waits whenever I checked it, but I think it was lying.