Now, x is unassigned but assumed. All correct in terms of properties. But it's too late to change now. They're quite consistent, but often misunderstood. The type of a maple data is the datatype of it.
Maple is a package for symbolic mathematics.
So data in maple are not only mathematical object like integer, reals and complex numbers but also the objects of the mathematical language like symbols and terms. Well, and the datatype of x is string. In maple, as in real life, strings are used as mathematical symbols. And if you think that x is a symbol for some complex number, it is still a symbol. But this are quit different things.