It's very possible that individual intelligence has not evolved past its current levels because it is at an equilibrium, beyond which higher individual intelligence results in lower social utility. In fact, if you believe SIAI's narrative about the danger of artificial intelligence and the difficulty of friendly AI, I think you would have to conclude that higher individual intelligence results in lower expected social utility, for human measures of utility.
I don't see how this follows at all. The fact that increasing the domination of nature (aka power) of entities that possess non-human values is potentially bad for possessors of human values doesn't mean that possessors of human values shouldn't try to become more powerful.
Using a historical example: The technology advantage of the Western powers was bad for Tokugawa-era Japanese values. That doesn't imply that Tokugawa Japan should not have invested in technology research, even if Omega guaranteed safety from Western incursion. Deriving the conclusion that increased power was bad for local values requires research about the sociological effects of various technological changes.
An interesting new article, "Cooperation and the evolution of intelligence", uses a simple one-hidden-layer neural network to study the selection for intelligence in iterated prisoners' dilemma and iterated snowdrift dilemma games.
The article claims that increased intelligence decreased cooperation in IPD, and increased cooperation in ISD. However, if you look at figure 4 which graphs that data, you'll see that on average it decreased cooperation in both cases. They state that it increased cooperation in ISD based on a Spearman rank test. This test is deceptive in this case, because it ignores the magnitude of differences between datapoints, and so the datapoints on the right with a tiny but consistent increase in cooperation outweigh the datapoints on the left with large decreases in cooperation.
This suggests that intelligence is an externality, like pollution. Something that benefits the individual at a cost to society. They posit the evolution of intelligence as an arms race between members of the species.
ADDED: The things we consider good generally require intelligence, if we suppose (as I expect) that consciousness requires intelligence. So it wouldn't even make sense to conclude that intelligence is bad. Plus, intelligence itself might count as a good.
However, humans and human societies are currently near some evolutionary equilibrium. It's very possible that individual intelligence has not evolved past its current levels because it is at an equilibrium, beyond which higher individual intelligence results in lower social utility. In fact, if you believe SIAI's narrative about the danger of artificial intelligence and the difficulty of friendly AI, I think you would have to conclude that higher individual intelligence results in lower expected social utility, for human measures of utility.