Since that wouldn't account for the season passholders, I couldn't see them doing that. It's not that much, either. I'd be mad if it were $10, but looking at it now, $5 isn't really that bad.
My thought on the issue is, they could easily have added 3-5 dollars to every admission ticket, whether you are thrilled about seeing Dino's are not. This way, if you want to see the Dino's, you pay 5 dollars, you hopefully enjoy it, and then you don't have to worry about paying the 5 dollars again.