Immigration can be extremely good for a country…

Work permits should be given if the immigrant:

- Works
- Pays taxes
- Doesn’t commit crime
- Isn’t a spy

If they fail at any of the four, they’re a drag on the country rather than a benefit. 

For green cards, the immigrant should:

- Demonstrated success in the above 4
- Shown needed expertise in a key sector
- Assimilation into the country / culture
- Not involved in anti-US or anti-capitalism activism
- Demonstrated that they have not participated in anti-American foreign customs like Sharia or a caste system.

And for full citizenship, it should include a strong civics test and fluency in English. 

I think it should be straightforward without unnecessary paperwork and kind of automatic if you’re just a normal person living a normal life, but it needs to be strictly enforced to ensure there aren’t any shenanigans. 

Caps by country are still needed though, especially for high population countries like India and China to ensure assimilation rather than creating a country within a country.