Blackstone bought Sea World, cut costs and cleaned some things up then IPO'd the company for a nice profit. Their only mistake was not selling all of it before that documentary came out
My only point is that going private doesn't necessarily mean it would be bought by someone who is looking out for the best long term interest of the parks. Usually the blueprint is buy low, cut costs way back and then sell while the profits remain high. A private equity firm will be looking into the best way to maximize their return when they flip the business and they will have huge debt to service so there may not be a lot of cash left over for growth. The grass is not always greener.