Even if there are a lot of people SW copes probably better than any other park. This is because there are relatively few "rides". A large # of people wanting to go on a ride increases the queue time quite dramatically, whereas most of the attractions at SW are shows or walkthroughs. Avoid wild Arctic immediately after a show at Shamu Stadium, many people come out of Shamu and head straight into the queue for WA, this can easily increase the queue time from a usual 20-30 minutes to more than an hour. JTA and Kraken may get busy so I would suggest riding them early in the day if you want to include them. For the shows I find that I usually get there at least 15 minutes before showtime anyway, find a good seat and use the time to have a drink or a rest. If the park is very busy, maybe it's a good idea to get there an extra five minutes or so early, but with the large seating capacities it is unusual for a show to get closed off. You might not get quite such a good seat, or even have to stand, but you're going to get to see the show.
Generally I've never had a problem as far as the attractions go , at SW due to a busy park. If there ever is a slight inconvenience it's that the restaurants can get busy at "peak times". I would suggest having a large breakfast outside the park and try not to lunch between 12.30 and 3.00. I'd either eat in the park about 3.30 and make do for the day, or grab a snack a little earlier and then eat outside the park after I had left for the day. I'm not sure how long it will be until the new shops and restaurants are open, but that will help this particular, occassional , problem.