Vry nice! It actually looks like UO may have better overall theming than WDW!
I see a lot of similarities to TDS.
Yep IOA has probably surpassed Dis on the themeing, but its kinda like saying who do you think was the best super bowl team, the 92 Cowboys, or the 93 Cowboys, both on a comparable level.
To me in the USA the top parks are Universal and Disney. Next is Cedar Point and the major 6-Flags parks, and the Busch Parks, but like I said they are in more of a super coaster park category, not a theme park (not counting Busch which has quite a bit of themeing).
But yes overall I would have to give the edge to IOA over Disney as to the exotic themeing. Dis is a very close 2nd. But also IOA/Universal has some extremely high tech cutting edge rides that have never been done before where they mix in 3-D with live action, great animatronics etc.
But if you have never gone, yes you have to go.
As for the 6-Flags parks, actually I think the one in LA is supposed to be the best. I haven't been in about 10 years, and they have added about 3 or 4 super coasters since I've been. Its a good park, but again, its a super coaster park. Its all about the coasters at those parks, very little themeing and really no theme rides, which is Universals and Disneys forte.