I think this post is almost there: what does not scale is humanity, our current constitution of largely selfish, immature adults operating as our leaders. In order for our civilization to scale, we need more real adults, and not these immature adult-babies running things.
That just leaves the attention seekers, and people with a burning agenda.
Saying that, what would make a good national politician and leader is probably quite a rare combination of traits.
Good understanding of politics (natch), law, history, economics and statistics (as well as possibly industry, marketing, PR, the money markets), and have a degree of personal charisma.
If the healthy ongoing survival of democracy needs that, we'd better get better at producing these people. England (sorry Scotland, but there is a bit of a gap there) and the US try to solve this with their OXBRIDGE and Ivy League Universities - but recently the results have not been so good. Maybe the upcoming younger generation can surprise us all?
It ends up like the clip on futurama, where Jack Johnson vs John jackson both end up talking about the 3c titanium tax going too far, or not too far enough.