Anybody know what a normal attendance total would be for a weekday during WorldFest/Festival of Wonder? I have absolutely no idea, so there's really nothing for me to compare with the 4,000 through the gate on Wednesday number. It doesn't sound too bad for a Wednesday in April, but maybe SDC is hoping for better numbers this year.
4000 people is a light crowd. To help translate that, it will mean that most rides are short to no waits, the train might run half full on almost all runs, and the shows won't be anywhere near capacity. A more "proper" weekday crowd that would actually be closer to meeting their budgets would be around 7000 to 8000 during the week.
Being below 4000 means there is a good chance they are losing money on that day.
Busier times of year you should see 9-10,000 on weekdays. Weekends shouldn't be below 12,000, and on a summer Saturday should be over 15,000. Busy days will have 18,000, and the Christmas crowds you're looking around 20,000. The busiest days the park has had are going to be in the 24,000 people range. When the park is over 19,000, well, those are days you don't want to be there with the long lines for everything and it feeling on the packed side.