To be within the attraction/theme park design industry you don't technically need a qualification if you have a strong portfolio of work and by strong I mean exceptional. You need to be able to draw, not amazingly well, just good enough to produce communicative sketches. You also need to be confident with adobe creative suite, 3D rendering packages and autocad.
The main skills I have are concept development, 3D design, master planning and communicative storytelling design. The industry is very hard to get into but start small and work your way up.
The reason I gained a BA hons qualification was mainly for the information and techniques I learned upon the course. Knowing this industry well I know that employees look for degrees within:
Architecture (part 1 or higher), interior design, museum and exhibition design, tv and film design and other relevant 3D related degrees. Graphics design is tricky as it is usually focused upon 2D design which cold get you a job within that sector signage etc but a graphics design degree that includes 3D elements would be beneficial.
I know a few of you will think sketching pffftt it's all computer now. Well your wrong, I fell into this trap and it is true. Development is done through drawings and sketches, clients like to see this stage drawn simply because they feel 3D rendered is too developed.
It's all about creating experiences. Your storyline is the key, you have to develop a strong storyline to be ale to have a strong design. Come up with a story, split it up into parts develop thoses parts, brainstorm ideas and you will achieve.
Sorry I went on a little bit but this forum is where it all started for me and I owe you guys a lot, I use to post loads all the time in here yeas ago on a different username.
If you love theming and design just do it!! I thought it was a dream and now it's not it's my daily routine of life.
I'll let you in on a little secret, this industry has more jobs than people able to fill it!!!
Oh. A little tip, not confident about sketching? Get a graphics tablet and use illustrator, a few months and you will be amazing! It's a skill that takes time to learn, so be patient and it will come.