Hi, Serena! If I could pick just one park which best engages the other senses and which is more conducive for people with sight limitations, it would be Epcot...especially if they are adults. Epcot tends to be less crowded than the other parks, and it has more wide open spaces for walking and less curbs and other obstacles. If your traveling party is adventuresome, I think Test Track and Soarin' would be great attractions for those who are blind since they appeal to more than just the sense of sight. Also, you'll want to take them to the Imagination! Pavilion and experience "Honey! I Shrunk the Audience!" and Journey Into Imagination with Figment. I think they'll enjoy the multi-sensory experiences.
Another great aspect of Epcot is the various dining opportunities. Your traveling party might enjoy the smells, tastes and sounds of Teppan Edo at the Japan pavilion, Nine Dragons at the China pavilion or San Angel Inn at the Mexico pavilion. Survey the group's tastes and make an advanced dining reservation for the day you're there. In addition, you may want to see how
Disney accommodates guests with visual disabilities by providing Braille guides and maps, audiotape guides and tours and attraction descriptions. One or all of those accommodations may help to enhance the groups' visit to Epcot. I hope this has helped you with your plans. Have a wonderful day and a magical vacation!