Immigration worldwide has experienced a rise in formal education. This is the case for immigration to the U.S. and I expect to the Commonwealth countries and western Europe. (Go here and here for the U.S.)
I have posted on the positive effects of migration from developing to advanced countries. Here is an overview found in a recent study the Migration Policy Institute.
The development of new industries in Taiwan, India, mainland China, and Israel have depended on international networks of skilled immigrants from these countries. Ideas for new patants tend to travel to developing countries through skilled workers from these countries living abroad and working at centers of research. Here is my posting about how the H-1B program spurred the development of the Indian IT industry.
Many youths in developing countries invest in education precisely because it gives them the option to access highway jobs abroad. (This is brought up in my posting about the Indian IT sector.)
Skilled migraines are as likely to send remittances as less skilled peers. When they do remit, they send larger amounts. Here is my posting that Nigerians, who on average have very high formal education, remit about ten times the amount per immigrant as Mexicans.
Countries become more democratic when large numbers of the students require higher education in democratic countries. The mechanism for this include the transfer of ideas, information, identity, and money by foreign trans individuals that might serve to interrupt repressive activities.
Many skilled workers are actually under employed or unemployed in their country of origin, so in many cases immigration can alleviate labor market pressures in developing countries. Restricting skilled nationals ability to leave their countries of origin has not shown to yield the intended benefits, and bring substantial cost. To take the example of African healthcare workers, there is no evidence of blocking international movement has reduced broad measures of morbidity or mortality. One sign of this is that broad health measures are worse than African countries that have experienced the least emigration of healthcare workers. In general, skilled worker shortages in developing states are not the result of migration, and instead have structural causes that go beyond the emigration of workers.