I am a certified coaster weenie. But I have managed to pretty much do every Disney ride, although with great reservation before riding the first time.
Thing about irrational fears is that rationalizations don't work as well as they should. Let me give you an idea of what I feel are the rides that might trigger some sort of negative reactions. If I leave the ride off the list it is a kiddie ride (which could be scarry for him like the magic carpet ride if it involves heights) or is not scarry at all.
I have segmented everything into Easy, Medium, Hard and Very Hard.
Easy - Should be easy to get him on, and should be easy on him when he rides with only mild thrills.
Medium - Provides possible for resonable thrills but most likely in a way that won't be intimidating from the outside, nor once he has given the attraction a once over.
Hard - Attraction probably has features that will increase his anxiety about riding before boarding and possibly extreamly thrilling to boot.
Very Hard - Extreme attractions (by Disney Standards) that are both very intimidating for people with fear of heights and extreamly thrilling as well.
Try him out on some of the Easy's see how he takes it. If he continues to speak to you without using profanities try him on some Mediums. If he has not served you with Divorce papers then give some Hard ones a try. Should he suddenly find himself a dare devil when he is in Walt Disney World then the "Very Hard" ones should be possible.
Magic Kingdom
Easy
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Pirates of the Carribean (small drop to the point of being silly)
Stitches Great Escape (involves suspense, but no motion)
Medium
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Bug Thunder Moutain - Could seem scarry cause it has a roller coaster style dispatch, but riding it especialy in the very front is anticlimatic and it obscures depth cues that would tend to cause panic in people who are afraid of heights. However he may be scared while looking at it, riding it should be resonable.
Hard
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Space Moutain - Its a very thrilling (not scary) ride. But it has a reputation that may precede it. The drops are not very sizable, its dark so once again obscures the view so no negative fear of heights effect. Scarry parts would be waiting in line for the first time and going up the chains to the top, but no big drop occurs so anticipation and fear are for not.
Very Hard
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Splash Moutain - Here's the interesting thing, even as you go over the top and see the drop, the fear of heights does not hit you, once again Disney plays seems to be playing with perspective. While it seems very high, it feels like the kind of high when your in an airplane, not the kind of high when your on a roof or ladder if that makes sense. (besides you come down pretty quick so not so much time to think about it). But they promote the big drop, you watch people go over what looks enourmous to those watching in line, and hearing the people screaming will only make him all to apprehensive. I did it and love it, but as always was anxious my first time.
Epcot
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Easy
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Maelstorm - Boat ride with a small drop, again nothing to speak of. Just drag him on and see how he manages.
Medium
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TestTrack - While many people may consider this a very thrilling ride, truth is it appears less thrilling when you approach it and logicaly the car only goes a max speed of 60 miles per hour on what is essentialy a flat course (yes it is slightly angled around curves). Tell him its "thrill" is moving at a rate which is probably slower then he drives on a daily basis on the freeway. With no hills or dips etc...
Soaring over California - This one is very relaxing when your not deathly afraid of heights. Once the chair has moved to the top position he will be fine, perhaps anxious at the beginning and the end as the chairs gentley raise/decend. My suggestion just tell him to close his eyes as the lights go out and then at the end when the fireworks start and we will have a pleasent experience.
Hard
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Mission Space - This should technically be medium but with all the hoopla about warning people over and over they may be sick and the fact the ride pulls a few G's it might be intimidating for him. Yes it will make him stick to his seat etc.... but there are no heights involved, and the experience is probably more thrilling then it lets on from the outside.
MGM
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Easy
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Star Tours - Its just a movie with a shakey seat after all.
Hard
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Rocking Rollercoaster - Ok based on the name alone and the dispatches with screaming, probably an impossibility to get him on. However it does all take place in the dark so no concerns about heights, and it launches, so once its moving he will be unlikely to be scared from that point forward. Thrilled yes, but irrational fear, nope.
Very Hard
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Tower of Terror - Probably not that big a deal for some. But if you have a fear of heights, being dropped is not the most pleasent sounding experience. Then you see super tall buildings, hear screaming people, elavators dropping quickly, probably a no go.
Animal Kingdom
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Medium
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Dinasaur - Its star tours on wheels with Dinasaurs. Moves quickly at times, nothing to make him afraid.
Hard
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Kali River Rapids - The drop is not bad, but to someone afraid of heights in line it looks scarry, not to mention the mild ascention up, which is also nothing but scarry in an irrational way. Get him on it and he will enjoy himself, but might be too intimidating from the outside to do so.
Very Hard
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Expedition Everest - Have not been on this one, but can't wait to go. Yes its high, but from the looks of it Disney is doing their usual to obscure any height refferences that would increase anxiety in people afraid of heights. But thats for the people on the ride.... from the outside watching people shoot down the moutain screaming.....I am thinking your not gonna get him on this one either.
Best of luck. Just remember, he will be happier on a trip that you take him on a thrilling ride (or rides) and he survives then coming back from the same trip having repeatedly chickened out of different attractions.