First, the reason it's repeatedly brought up is the obvious tie-in of a Halloween event and a television Halloween tradition going strong for 25 years. That plus the recent expansion of Simpsons presence in the park.
Second, it's ironic you're concerned about the cost of costumes but then suggest an entire ride overlay, which would be many many times more costly.
Third, it wouldn't be funny? Do you not find Treehouse of Horror funny? What planet are you from?
What about Halloween decorations through Springfield and an overlay of the ride with a new pre show and ride film.
What about Halloween decorations through Springfield and an overlay of the ride with a new pre show and ride film.