Inadequate Equilibria is a (freely available) online book about how and why our civilization succeeds at some things, such as predicting the future value of Microsoft stock, and fails at others, such as determining the optimal diet to remain healthy. It's one of the most interesting books I've ever read.

I could easily see this actually decreasing inequality. There is already a very significant genetic factor to aptitude in most areas. It's a major source of inequality, not necessarily between groups/races, but definitely between individuals. If genetic enhancement is widely available and superior to most levels of natural genetic advantage, then I think genetic enhancement might bring us up to a higher, more equal, playing field.

Of course, there's the possibility that genetic enhancement will be very expensive, and so lock poor people out of it. There are a number of possible solutions to this issue, but the most obvious seems to me to perform arbitrage between a family's current state of poverty and the future wealth their child will gain by virtue of their enhancements.

From the public sector, this would look like a tax on the population to pay for poor families to get genetic enhancement. The government would then regain the money they spent through the increased taxes that the genetically enhanced person would pay as a result of their increased income.

From the private sector, this would look like a corporation that would pay for a poor family's children to get genetic enhancements in exchange for, say, 2.5% of the child's lifetime earnings. Assuming genetic enhancement will improve your lifetime earnings by more than 2.5% (which you kind of have to in order to believe enhancement has the power to impact inequality in a major way), this is beneficial to the child. If we assume yearly earnings of $28,000 (from Wikipedia's Personal Income in the United States) and working for 40 years, this gives us $1,120,000 of lifetime income, which is enough to fund a $20,000 procedure and still have a corporate profit margin of $8000 per person.

Ultimately, the only way genetic enhancement has the possibility to influence income inequality levels is if it can increase the lifetime earnings potential of the people who receive it. Once you grant that premise, you create an investment opportunity where people with money now can get more money in the future by paying for other people to get enhanced, in exchange for a small amount of the enhanced person's future earnings. I doesn't matter if the person with the money now is a corporation or the government. The investment opportunity still exists.

The only possible world in which this doesn't work is if the cost of the procedure is very close to the increase in income that enhancement grants. But even here, genetic enhancement doesn't change inequality much because the people who are enhanced would benefit almost as much from just having the money given to them, so it's not possible for rich people to become unassailable super-rich by genetic enhancement. They loose almost as much by paying for the procedure as they gain afterwards.

There are many possible issues with genetic enhancement, but I don't think inequality is one of them. (That is, unless the government outlaws the private sector method I described and also fails to implement a public solution. Then things could get bad...)

The primary argument for killing them seems to be that it would help protect humans. The primary argument against seems to be that there might be environmental consequences.
Consider if the situation were reversed. Imagine that mosquitoes were currently not killing any humans, but were in danger of going extinct, and there might be environmental consequences to that.
But wait! Fortunately, we have the ability to save the mosquitoes. All it would take is for some 500,000 people to be sacrificed each year! Now I know this may seem a bit unethical, but most of these people are in very poor countries, so the don't really count, right?
When you put it like that, the two sides don't seem so evenly balanced. It becomes pretty clear that our moral obligation is to exterminate the mosquitoes that spread disease to humans as soon as we can, using all the tools at our disposal.

Some people also bring up the possibility that wiping out mosquitoes will give an opportunity for something worse to appear. I don't think this is a good counter argument.
First, it is never used for any other species that poses a similar health risk. No one would ring their hands over the possibility that wiping out HIV would cause something worse to replace it.
Second, there really isn't a mechanism by which wiping out mosquitoes could present an opportunity for another species. Mosquitoes don't compete with other blood-drinking insects the way foxes and coyotes compete with each-other over rabbits.
Foxes and coyotes both have a certain rate at which they consume rabbits. The rate at which foxes consume rabbits plus the rate at which coyotes consume rabbits must be less than the replenishment rate of the rabbits, or over hunting occurs. As a result, a reduction in the number of coyotes means there can be more foxes.
But mosquitoes and other bloodsuckers don't compete like this. The total amount of harvest-able blood is not much reduced by mosquito activities. 500,000 people/year out of around 7,000,000,000 people = around 0.007% of the world population per year. True, this rate is much higher in high-mosquito regions, but even with very generous assumptions, it's unlikely to rise above 5%.
The upshot of all this is that wiping out mosquitoes won't suddenly cause a huge increase the amount of food available for any other species whose food source is similar to the mosquito's. As a result, any species that would be enabled by killing the mosquitoes should already have appeared, because the environment is just as favorable for them now as it would be if we were to kill the mosquitoes.