Would love some thoughts on this question as I figure out which ride to do first/whether I should skip one or both. My intention was to start with Pirates and if he did ok with that, do Haunted Mansion, which is one of my personal favorite rides. But I've heard from some people that's a bad idea because many little kids are more afraid of Pirates because it's both darker and louder, and starts in darkness with a bit of a drop. FWIW, I have shown him videos of both and he says he wants to go on both of them, and seems particularly intrigued by Haunted Mansion, but he's 2 and probably has no idea what he's getting himself into! Would also love to hear personal experiences of any other 2 and 3 year olds!
Neither would have worked for my three year old, but everyone is different. In fact when my son was three we decided to do "It's a Small World" with him, and he said, "Mommy please don't make me go, I'm scared.". This was not my best mom moment, but I said, "This ride isn't scary at all. You know the song. Get on the ride". Anyway DS 3 was terrified of those dancing dolls and screamed for the full 12 1/2 duration of the ride (honestly it sure felt longer than 12 1/2 minutes to me), ruining the ride for everyone in our boat and the boat in front of us and in back of us. I felt terrible, and I never made DS get on a ride again he didn't want to. A very nice man in his 50s came up to me and DS after that ride and very seriously said to DS, "You know I always feel like screaming on that ride too, but at my age it's not acceptable.". Anyway, I still to this day appreciate that man's kindness. This also did not in any way ruin my son for life lol.
At three my son's favorite thing in all of Orlando was playing at our condo swimming pool. And the only park that he really enjoyed (was totally into) was SeaWorld.
I'm happy to say that at six DS wanted to do "It's a Small World" and liked it. He did Pirates at age 8. He waited till 11 to try Haunted Mansion and didn't care for it, but it was his choice to try it. He didn't like Haunted Mansion at 11. He found to be a little scary and thought the technology was a little lame and old too -- or at least that's what he told me. Then in high school at age 14 he tried it again and liked it.
All that being said, I would say Pirates is less scary than Haunted Mansion or was for my son at least (the ghost stuff was freaky to him while the pirate stuff was just fun). Some kids, though like my son, and this may not be all that common can be freaked out by dark rides (And Disney has a lot of those). SeaWorld was by far for us the best park in Orlando and the one my son enjoyed the most up thru age 8 (worked so much better for him -- had a real love and fascination with fish and marine mammals and a real fear of most of the Disney dark rides.) DS is 28 now and he and we still really love SeaWorld and it's DS's second favorite park in Orlando now behind the Magic Kingdom. From age 14 on, he really enjoyed all the Orlando parks, but the MK and SeaWorld are still favorite stand outs.