Here's something I think they could try to add to make the tycoon part of the game a bit more interesting...
They currently have some basic elements of a time-of-day, though it feels sort of half-implemented. If they completed that, and introduced changing weather, there would be some good opportunities to affect the gameplay:
* When it's raining guest numbers drop overall, and the guests that do come will prefer rides and areas that are covered
* When it's fair weather you have normal guest numbers and a normal spread of ride preferences
* On very hot sunny "perfect" days guest numbers are higher and outdoor rides and particularly water rides are highly sought after
It would add another layer to things - have it so that you can adjust things like prices etc. using a schedule which reflects the current conditions - maybe you want to charge just a little more for those cool slushies on the hot sunny days, and close the slushy shops down completely on the wet days etc...