Most parks have long lines, but I agree I wouln't wait 3 hours in line for a ride. I draw the line at one hour. After that the ride just isn't worth it if I can complete 3 other rides or eat, etc. in that time frame. The Chicago Six Flags (I live about 15 minutes away) will take serious waiting on the highway just to get parked if you don't know about the rear entrance. The park itself has plenty of capacity, the ride lines are a different issue. Here's some secrets for going to parks (shh, don't tell):
1- Take a day off and go on a week day. You can also call (or otherwise discover) which are their light visitor days. Some parks also have rear entrances to parking also which can save a lot of time. If the forecast is for rain there will often be less people there that day.
2- Decide ahead of time the best rides you want to go on. Then be there as the gates open, and go directly to those couple rides first, which are typically deeper into the park. The common people sort of drift in and fill up the park front to back. Some rides are just always long lines if popular. Just deal with it or go do some other ride or event. Don't blame the park if you have it in your head to ride something no matter what. Decide how best to invest your time.
2- Get your hand stamped, and have a cooler with lunch in your car so you can take a break and don't pay for their low quality/high cost food. Don't buy water (it costs $15 a gallon), get other drinks when possible.
3- Check at the info stand about discounts. For instance, at our Six Flags on the way out in th evening you can buy a Next Day pass for about $7. So we bring the kids the first day and let them do whatever they want. Then just my wife and I return the next day for the serious coasters. You can also get discounted entrace tickets at local places like major employers, banks, credit unions, some stores.
That's all the secrets I can give out today.