Ok, I will voice my 2 cents worth. I may have a different prospective of this since I have raised 4 kids through many vacations and have taken grandkids as young as 18 months on a
disney cruise. In other wards i am OLD and been there, done that!!
I would take him. We had our 18 month grandson with us on one cruise. He was afraid of the characters and NEVER went to Flounders, but we woke up with a big smile and it stayed their until he fell asleep at night. You couldnt wipe it off no matter what!!! He had a blast, he loved the shows and the splash area (Mickey ear) and all the food and attention from people.
Yes he was a lot of work for us, but the awesome memories we have are so worth it!!! Now I will admit his parents were there too but we had him 90% of the time and he even slept with us in our cabin some.
Even remembering the good and not so good of family trips with our kids when they were younger, now even the Not so good are the best memories we have.

I wouldnt change them for anything.
We were like Jeff, we took the kids everywhere. Mostly camping trips. Our oldest was camping before age one and yes it was work for us but seeing her have fun was so worth the extra work.
Now it is just us and we can have all the alone time we want and we do love our times together, but the memories we have you just cant put a price tag on. Yes I went through a lot of excedrin a couple of times
just my opinion, but I would never turn down the chance to make more family memories for myself. That is precious and nobody can ever take that from you.
Kathy