Some people love the midday break, but it's not really that practical to do more than once in a while. The extra 1-2 hours on or waiting for transportation will eat up the time you'll save from shorter lines. Time is money at Disney World so you have to weigh how to not be on busses all day.
I'll add, If you are staying at a Deluxe resort like CR, Poly, GF, BC or BW then midday breaks are more feasible. Especially at the CR/BC/BW since you can walk. But anywhere else you are adding two bus rides for each trip. When we've gone back to a park twice in a day we've been at one of these close resorts. We'd do maybe 9-1, then back, then 5-whenever. Break it into around 4 hour blocks.