Well here I seem to agree with Corb, city min dist sucks, it sucks big time. anything beyong 2 is majorly retarded. You can't build city vecause of city you can even see? Real fun times. I would advocate city min dist 0 ;P. As for smallpoxing, it is laready severly limited (I think to the level of "shame"), so I'd say deal with it.
As for city radius, you need to edit ruleset, it's quite simple, impacts of that are harder to quantify. I experimented with all kinds of stuff in rulesets, city radius was one of them. So if anyone needs any help on that, I can conlust/edit ruleset.