I love it when people say, you should take your children to all these cultural places, for Ds2 it would be like taking a teenage New Yorker to an Amish village and expecting him to be astonished. But get him on a bike and he will ride for hours in the countryside, or he will walk for hours and hours. Stare at a landscape? Eat questionable food (his teacher went to Vietnam and ate everything) absolutely not for Ds2. 
We took the children to Disney World for the first time when Ds1 was 11 and Ds2 was 7. He turned 8 whilst we were there and had his 8th birthday with his favourite character, Pluto at Chef Mickeys.
We have returned many times since then, we absolutely love it.
We did the 7+ thing for several reasons, firstly the flight. Having been on a long haul flight with other people's children the idea of trying to keep a child in a seat for take off/landing and turbulence would have been hell. Secondly the heat and humidity depending on when you go.
I followed YouTubers for Disney way before we went and they now have a child, watching them try to get their baby/toddler (they are DVC) to drink water all the time to keep them hydrated just feels stressful. Plus the possibility of overheating. Also depends where you stay. We stay on property, so no car, just Disney buses or walking (Universal) and I didn't want to hire a pushchair and park it up.
For me holidays are about relaxing, hence why I waited to do long haul with the children. My friend has been every year to either Disney World or more recently Disney Cruises. Maybe she has easier children and is more laid back 