If you arrive early, most likely not. Wait times are moderate this week, and arriving early (preferably at park opening) will allow you to complete a large chunk of the park's attractions.
If you prefer to approach the park with a more leisurely pace, a Front of Line pass might be worth it. It'll certainly reduce the anxiety of completing rides when you arrive, and it'll allow you to spread attractions out throughout the day. Remember that shows have scheduled showtimes throughout the day, and arriving 20-15 minutes early will usually allow you and your family to grab a good seat. Once you finish the bulk of the park's rides, you can flulff your day out with shows and rerides if your schedule allows.
Keep track of the hashtag [HASHTAG]#Potterwatch[/HASHTAG] for Soft Opening updates from people in the park. The main Inside Universal twitter account has also been posting daily updates on Potter Softs. Hope this helps!