It's been suggested before that it's kind of uninteresting. Given that it's meant to honor a successful endurance from a siege I had two additional suggestions for abilities. The first is that it is a triumphal arch in the city it's built - in reference to winning wars. The other is that it triggers the agrarian ability when the city is sieged. 

noice

Thanks!

Although i really like both of your suggestions, i think it should just get changed entirely. There is very little reason in building a defensive wonder, i feel like if you are pressured and need to go on the defensive you probably won't be building wonders.

But if they want to keep it as a defensive wonder. My 2 suggestions would be make it give bonus combat strength to all home guard units, similar to the one civic you can unlock. Reason being that would actually make it synergise with militaristic cultures who can raise those as amries.

Alternatively it should allow us to build even when the city is under siege.

Getting the victorious award was meant to be something that gives you extra support for winning a war - one way to win a war is to endure. It occurs to me that to make this ability much stronger and double down on the defensive nature of the city is that the city has to be sieged for at least one turn before it can be attacked. It's a bit arbitrary though.

I like the last suggestion that'd be quite a unique bonus befitting a wonder and it'd make building tall with a capital a bit more feasible. 

There is one problem though I think that it's been stated that you can't build districts because it affects the generated battle field. Cities can build under siege. But it's mostly infrastructure. I can't remember if they suffer penalties though. I guess with the Colossus the very least it should do is removing those penalties from being sieged. 

I know someone else floated the idea that whenever your cities are attacked/sieged fortresses you now spawn 1 additional militia reinforcement in any legal land spawn location.

SmileyD wrote:

Alternatively it should allow us to build even when the city is under siege.

Good idea!

I think I'm convinced.
I think a faction wide +2 str bonus to all Militia for the Empire. "Colossal Will"
A city specific bonus - the perks of globalism - the city can trade during Wars.
And.
A separate bonus than Rome but a similar effect - maybe a bonus of 1 influence to all military buildings for 10 (+/- game speed) turns. "Colossal Victory"