LLK is quite right in what she says. With normal larger varieties we have to shorten new growth constantly and thin branching occasionally. These dwarf varieties need shoots shortened very rarely but need thinning often or they get too crowded resulting in dieback.
Defoliation is used mostly to increase the number of shoots. These dwarf maples grow too many shoots as it is so it should not be necessary to defoliate unless maybe you were growing a very small tree. Defoliation will not hurt this tree, its just a waste of time.
