When I look back at my last few trips (only 2 park days) that included myself, wife and preschooler we weren't very efficient, but we didn't care.
Since there is more to do at WDW than just "rides" (there are shows, streetmosphere, meals, shopping, etc.) and plan on going back a lot I try not to push it. Sometimes those non-ride experiences are even more fun and memorable than the rides themselves.
But let me give you some numbers:
Last trip I was with my son (4) and daughter (5mo).
Day 1 - DHS and MK
Star Tours, TSMM, Launch Bay (including a M&G), build a droid at Tatooine traders, Star Wars Show, Watching the March of the First order, break for lunch waiting for express bus.
Hop to MK with Express bus (probably about 20 minutes).
Carousel of Progress, Buzz (FP), SDMT(FP), Carousel, play with the Sword in the Stone, Peter Pan(FP), Country Bears Jamboree, shop at Pirates, dinner at Skipper Canteen
Time - 8:00 am to 6:00 pm
Epcot
Test Track (broke down longest wait of the day - 45 minutes), Spaceship Earth, Soaring, Lunch at Garden Grille, Living with the Land, Finding Nemo, Turtle Talk, wander around the aquarium, wander through world showcase to see topiaries and get photo pass pictures.
Time - 9:00 am to 5:00 pm.
As you can see .. not many "rides" .. we average about 1-2 "things" per hour as I didn't really want to push it with the kids. We are just slow moving with infants/toddlers/preschoolers -- I mean a bathroom break could take 20+ minutes
.
We definitely get more done from RD to Noon than noon to 5 usually .. (naps, breaks, shows, etc.).
If I wanted to really be efficient and push it (like if I was just going with my wife), I could probably easily get 2-3 "things" done per hour.