There are several jabber:x:data form types defined, and it would be good to provide a better (less generic) way to modify those forms than accessing the field by var, casting field type, and then setting its value.

One of the improvements would be a way to access fields by using an enum instead of field var (which would allow automatic field type casting). Another one would be providing different classes (based on JabberDataElement) which would allow data form manipulation by accessing those new classes fields.