I don't know man. Maybe an app for phones but it gets harder from that when you try to create finer details. I think having an accessory made for Dreams is the best way. Even xbox makes controllers for people with disability. I think Sony should also try targeting specific audience even if there's not a lot of profit but the thought is highly appreciated.
Looking at the demos with Move it doesn't seem like much of a problem.
Either way I am not disagreeing with having extra devices that work with the creation process, but rather making Dreams themed peripherals. That is overly expensive and without any idea of how well Dreams is going to be received (if social media and online forums are an indication, the answer is not that well), it would just be a money sink to do so.
Making other devices compatible with Dreams creation is the most logical step, and infinitely cheaper and safer I feel.