Or perhaps you haven't done every thing on every trip.
We have. If you're referring to other experiences that cost extra money whether in or outside of the theme parks, sure, there's more to do. If you're talking about things to do inside the parks included in your admission, if you've found multiple new things to do in 8 trips over 3 years, then you obviously weren't doing everything in the parks. Which is fine. Point is, there aren't that many new things in the parks. Unless, by my math, you've uncovered at least 24 new experiences over the past 8 years. If you have, please share them with the rest of us.
I would be shocked if you really and truly have done everything there is to do at every park
Is the number 24 coming from 8 trips in 3 parks? I'm not sure where your number is coming from; however, somethings are really easy just by going at different times- off the top of my head.
1) Food and Wine
2) Flower and Garden
3) Fourth of July
4) Christmas/ Christmas party
4a) Jingle Cruise
5) Be Our Guest Restaurant
6) Under the Sea
7) Enchanted Tales with Belle
8) Princess Fairytale Hall
9) Festival of Fantasy Parade
10) Seven Dwarfs Mine Train
11) Celebrate the Magic Castle Show
12) Anna and Elsa
13) Star Tours (re-opened just over 3 years ago..)
14) Sorcerers of the Magic Kingdom
(only including things that we do/would do (haven't personally done the Mine Train yet)- there are other things at like Wilderness Explorers, the meet and greets in Storybook Circus, Legend of Jack Sparrow, that we don't do)
and things that cost more money but I still include because they're new... especially dining because that's a huge reason why we go to Disney... (if you can't tell Epcot is our favorite park)- again only including places at which we've actually eaten
14) Spice Road Table
15) La Cava
16) Tutto Gusto
17) The ice cream martini place in France
18) refurbished Cali Grill
19) RunDisney events (Wine and Dine)
then there are things that aren't necessarily new but new to us
20) First time at JellyRolls
21) First time bringing our twins (February 2015) which will make everything old new again
22)Staying at new resorts
23) First time Drinking Around the World
sorry I fell a little short of 24 and I broke some of your rules but I'm sure there are other things I just can't come up with and your rules are arbitrary anyway- we are just as excited about a new restaurant as a new ride and are excited to be entering a new phase in our lives where we can enjoy the "kiddy rides" again through the eyes of our children.