I can't argue much with those themes, though I am not sure that race v. environment is really any different than geographic success or failure. I think that you should be sure, though, to get the importance of agriculture in there as a theme. I think that maybe you could replace race v. environment with that or maybe conquest. Anyway, Diamond certainly does spend a lot of time talking about why it was so important to have agriculture.
Implications? That's hard because they're largely in the past. But one implication is that we should not pay too much attention to things like culture when we are trying to figure out which societies will succeed. We should also not think that some races or cultures are superior to others.