I remember when the park didn't open until the first day of World Fest in April. To be honest, I think they ought to go back to that. For the most part, any new rides are either not finished or it's too cold to open them in March. Several shops stay closed, and then they always underestimate the attendance numbers, so food supplies run out, etc.
And then, it's usually just too darned cold in March to really enjoy anything.