Civilization games with snowballing effect

When playing Runewars last night, I noticed that it lacks snowballing effect. Inversely when I played Imperial Settlers the game completely snowballs.

So, which civ games have this effect pronounced? And which doesn't?

I know for sure games like:

Mare Nostrum and Age of Renaissance have crazy snowballing effects.

Games like Vinci has snowballing affects, but also has built in leveling affects, so can go either way.

I think you have to look for games with decline or decay that tend to reset each era and make it level out.

This is a pet peeves of mine in games like Age of Renaissance and Civ/AdvCiv. There is only a snowballing effect if the other players let it happen. When one player is getting ahead the other players need to do something about it. You won't attack the leader because you really need Law next turn? You keep trading with the leader because you really need just one Oil card? None of that means shit when you're helping the leader advance his position with your actions.

I like games that require the players to balance it out, but it drives me nuts when the players don't balance it out and then call it snowballing or run-away leader.

I haven't played Imperial Settlers so I can't speak to that one.

What I mean here by snowballing effect is not one player steamrolls the others (the rich gets richer), but more as the game go you get substantially more actions and choices. Sorry if I didn't make myself clear here.

Imperial Settlers is based on 51st State, but Trzewiczek pulled of all the stops on the engine. In the earlier games you can only do X Y times, A, B times. In Imperial Settlers, you go on, do anything and build anything until you run out of resources since resources are not kept to the next round.

You can build (and make deals) to add your income, you can add more actions, and the crazy thing is, you never have bad choice. It's not rare to pay 1 food, to get a food AND a building that produces it every round (ok this is a lie, but this kind of things happen). This is truly an empowering game, with very little penalty. If you play your hands well, you can go on and on. And with more buildings your civilization has, you get more choices and your hand becomes more versatile.

The game only lasts 5 rounds though, so it understandable if it wants to snowball like crazy.

It's like the computer game in which you start with a city and a military unit, and later you get like 4 or five cities with dozens of military unit.

On the other hand, in Runewars if you have a big empire, you're still restricted at one action per turn.