:
"shut off razing" flag: oh man - how this would make my job so much easier!
'smart' AI arty usage: imagine if the AI rolled up on 'ya w/ a SOD loaded w/ arty pieces?!
"nuclear differentiation": by this i mean that i would like to see a scaled range of sort wrt to the effects of a nuclear bomb. i mean, the "Fat Man" over Nagasaki was much less powerful (by a huge margian really) than say a "Peacekeeper" ICBM.
a "shut off pollution" flag: again, this'd probably give me a few less headaches.
ability to allocate a specific movement rate for rails: ie - none of the 'insta-move' aspects of the existing rails. sure you could leave it in there (sort of like the 'infinite bombard' flag for air units). but to be able to eliminate that 'insta-move' aspect would be a good start.
additional culture groups: duh!
enhanced 'alliance-war' settings: say, for example, i want to flag one nation as 'never declare war against
country x' but not be in a 'locked alliance'. more allowable alliances through the editor would be nice also.
more differentiations in terrain tile bonus-maluses: say i want to flag LM Mountains as impassable but allow for the standard Mountain to be traversable.
there's probably dozens more stuff i could think of - and i know a few of you guys would be able to rattle off a buch as well. all food for thought