There are those, particularly among the libertarian ranks, who are of the mind that an uber-intelligent society is not optimal because there still must be people to wash the dishes and pick up the trash, something those of modest intelligence are putatively better at doing than brainiacs are. But even in an industry such as trucking, higher IQs make for better truckers. And more intelligent people cause less in the ways of costly externalities like crimal activity and poor health. They are also more likely to come up with more efficient and effective ways of doing menial jobs in addition to the more complex ones, and add societal value without recompense (Linux, the blogosphere, or free media-inspired entertainment). For a fuller refutation of the fallacies in this strain of thought, see Randall Parker's classic post, Benthamite Libertarian Collectivists Wrong On Open Borders.
Equality of outcomes is not generally at the top of the libertarian's priority list. It is for many on the left, however. So here's a reason for the left to support policies aimed at raising average IQ (merit immigration, welfare for sterilization, progressive child tax credits, etc): More intelligent states are more economically egalitarian states. As of 2006, the correlation between a state's average IQ and its gini coefficient is .68 (p=0). This means nearly half (46%) of the income inequality in a state is explained by its population's estimated average IQ.
Unfortunately, another ostensible top priority on the left is the maximization demographic diversity, which is at odds (not just in actuality, but even tautologically) with equality. At Taki's Magazine, Austin Bramwell and Robert Spencer have come up with two broad distinctions in libertarian thought, the comic (optimistic) and the tragic (pessimistic). I prefer a binary distinction based on ends and means, and conceptualize the comic and the tragic accordingly. That is, the comic wants ecumenical freedom for the individual and is focused on maximizing positive rights for him in every context, while the tragic is concerned with ensuring what might be termed "cultural federalism" or more simply just "localism"--allowing people to have a hand in determining the laws, mores, and ways of the societies they live in, whatever their nature.
On the right, there are perhaps three major sub-categories of conservatism: The social, concerned with things like abortion and same-sex marriage; the fiscal, concerned with taxation and governmental wealth redistribution; and the national security, concerned with ensuring the US maintains strong, ambitious military capabilities on the global stage.
Is there a similar set of broad distinctions on the contemporary Western left? From my vantage point, an obvious perforated edge along which to tear it in two is on the primacy given to egalitarianism (of outcome, not just isonomic) or to maximizing demographic diversity. I've not seen this distinction given much thoughtful treatment in the US. In Europe, diversity seems subjugated in importance to egalitarianism, and is promoted more as a consequence of equality than as an ends in itself. That is, Muslims vociferously advocating the adoption of sharia law in the UK are supported by the left because they don't want to be seen as limiting the rights of a specific group more than because they want to increase the size of the South Asian and Middle Eastern population in their country. I might be wrong on that, though.