Well to make your life easier it might have exported all your contacts to a single .vcf file.

I don't imagine that people importing hundreds of vCards is a normal use-case. If it's a specific problem for you, as you can't use sync or go back and export as a single .vcf, the code necessary to import them is pretty simple so you could write yourself a little app to import them all.

When I moved from my 6300 I just told PC Suite to backup my contacts, attached the N900 and told it to restore them to it.