I'm wary about the idea of a complete solution. Rather than trying to create a sudden revolution, I think we should improve the world gradually. My vision is that people slowly become more utilitarian. If we want to achieve this, we ought to focucs on topics that
1. Are on the edge of public consciousness: they are not such far-flung ideas that they turn people away from utilitarianism
2. Are high-yield: they don't just make a difference, they're super-effective.
I suggest that:
1. We ackowledge speciesism (it's wrong to value a different being differently because of its species. What matters is whether a being can suffer). Then, we reduce our intake of animal meat and animal products. Hopefully, we'll stop altogether.
2. We donate money to alleviate poverty, as suggested by
Peter Singer's shallow pond analogy.
There are other issues worth considering that do not quite fulfil my criteria:
3. Climate change. It's real, but what is its effect on wild-animals? Could it decrease the number of wild-animals suffering in the wild?
4. Technological Singularity / Transhumanism / Futurism: It's possible that some technology is invented that greatly contributes to or detracts immensely from happiness. But can we do anything useful about that now? I don't think there's any point trying to have a public discussion about these topics because noone's listening. The best way, it seems to me, to ensure we manage future technology well, is to spread the idea of utilitarianism itself. Utilitarianism will be a powerful mental tool no matter what technology arises.
5. Reducing existential risk. Wild Animal Suffering: Likewise, these projects are far from public consciousness. They're not close to acceptable ideas.
6. Abortions. Euthanasia. Medical ethics. Although medical ethics is a really emotional topic, it probably doesn't include as much worldwide suffering as something like poverty or speciesism.