I think it's dangerous to categorize people like that, or even categorize people at all. Each individual act differently, has different attributes and flaws, and should get treated differently. To put people in a group and devise policies to treat the whole group the same, without any regard to the difference in each individual, without considering the nuances, is one of the major flaws and evils of central planning.

With that being said, I believe the following to be true: every nation, including those self proclaimed "first world" countries, need productive individuals, regardless of where they are from. Productive meaning they create value by thinking, creating, working, and voluntary trade with other people. At the same time, I think that no nation, be it "first world" or "third world" should want freeloading parasites in their country.

Ultimately, it is not a matter of first world vs third world, but productive vs parasitic. If it were up to me, I'll take as many "third world immigrants" as possible, as long as each individual is productive and creates value for others.