We have been going at least every other year since 1982, in the past 5 or 6 years at least once a year and some years 3 times and there are still a number of things we haven't done.
MK - we haven't done most of the kid's rides don't know why we didn't do them when my kid was a kid but we just didn't. We haven't done Magic Carpets, Dumbo, Teacups, Astro Orbitor, Carousel, Laugh Floor, Tiki Room and up until last Oct. Small World (that one I was proud of). We haven't done any of the formal meet and greets, back when my kid was a kid, the characters just kind of roamed around and he probably met all of them. Oh and we haven't done Enchanted Tales with Belle. I don't see us doing most of those any time in the future except maybe the Carousel.
AK - we haven't done anything in Dino Land, we just walk through it. We did the bird show before it was Up but not since. We have never been on the train to the kid's part (can't remember the name of it). No character meet and greets.
HS - Mickey & Minnie's run away train and the new Astro thing in TSL are the only things I can think of there. M&M wasn't open the last time we went and my son doesn't do spinning things. I will most likely do both on my next solo trip. I met Chewie but we haven't met any of other characters there.
Epcot - Mission Space and Turtle Talk are the only things I can think of we haven't done there. Won't ever do Mission Space. No meet and greets. Oh, we haven't see the new movies but saw all the old ones.
So basically most of what we haven't done are kid's type things, since my kid is just shy of 40 I don't see us doing those. There are a lot of things we won't do again - RRC, Star Tours, probably EE, Kali River Rapids (I don't like getting wet) and my son has nerve damage in in spine so RRC and EE hurt, Star Tours makes us both sick.