Well yes, like many have said it depends on the time of year you are going, the type of ticket etc. If you go during colder times, it shouldnt really be that crowded, if its summer then expect long lines.
What I do, is go to a waterpark a day, Ive only done both one time during spring break. Get there as soon as it opens, if its BB(Blizzard Beach) Ill usually do Summit Plummit about 3 or 4 times FIRST simply because that line fills up pretty fast, if you choose to walk to summit plummet, you will definately get tired and if you plan on doing it again, if you are anything like me, you will be done by the 3rd go around. Then after that Ill head for Downhill double dipper because thats another one that seems to fill up fast, everything after that is pick and choose, and for BB, Im usually done after an hour, then Ill head back to pop half century, clean up and go to a theme park or take a nap. TL is different though, so it takes a good 3 hours for me to do everything, like BB get there early and do Crush N Gusher first, its really one of those slides that you DONT want to wait in line for, because it looks like its long, but each one is pretty short. So if you get there at opening you'll have the chance to do each slide several times without waiting in any kind of line, and its much better because each slide is different and if you can go over and over again, its better than waiting and going on one, but they all are pretty short.
Thats all I got for you, hope u have fun and good luck.