A qualified "yes and no" is the answer to that.
Many WYSIWYG apps can import complete sites via FTP or HTTP, but the results may not always be perfect. For example, I am aware of that older versions of Net Objects Fusion were described as weak at site import. I have no first-hand experience of FP at all, so I do not know how reliable its imports are. DW is likely to be better, I suppose, but I have never used that for imports. I prefer to hand code and certainly don't use WYSIWYG apps to edit existing sites.