The Sumerians LT needs some work. Here it is for now:

And it is a miss for the first part. I won't discuss the discount on treaties with IP, I think it is quite good but hard to assess.

No, the topic here is the crappy reduction to attach territories to a city.

It is obviously made to play a bit taller than usually and that is great. However, in practice, it fails. It doesn't offer a reduction big enough to be sensible. To benefit from it, you have to either play with few cities and you'll then get a very little discount of 10% or 20% at best in the later eras, or try a single city challenge. In the first case, the reduction is small and less useful as those cities will each have some territories added to them. In the second case, the price of attaching territories stays a limit. Attaching a 25th territory, even with a 50% discount still costs a lot. And to get the expansionnist stars, you need to attach many of them.

So, numbers have to get tweaked. I can offer the following solutions:

1. a flat -50% right from the start. It won't help late game but will help prepping enough influence for the late game, maybe enact few more civics, etc. and incentive players to go tall early. I actually think this number could even get to -75% and be limited to the capital.
2. a bigger reduction, like -25%. It might lead to free attachement that would encourage exploits to buy stuff with influence, which is not neat so:
   1. It could be -25%, then +25% from what's left (so 75%, around 18,5%), then again from what's left, etc. With a city cap of 4 and 1 city, the reduction would be of around -58%.
   2. Make it diminish with the discrepancy? -25, then -20, then -15, then 10 forever? For a city 5 below the cap, the bonus would not be of 50% but 80%.
   3. Cap it at -75% or even -90%?
3. Make it free each era to attach the first 3 territories on the capital.

The numbers seem big? In a way, they are but playing tall is so difficult that those numbers are almost a requirement to be able to play below the city cap. Even playing around industry, building districts starts to be tough at some point, as players tend to buy harbors or extractors. Some RQ in the second half of the game take soon a lot of time. Plus, even with the discount on attaching territories, there's a need for influence. The go to road is the Liberty axis but it is impossible to buy or build the EQ in 25 territories. Even early, the need for stability pushes towards the embassy, Stonehenge, stone rings, giving little time to build the EQ and if those are not providing Industry, they'll amper later development. All this coming from a player that generally refuses to build industry and can still win at the highest level in solo games.

I heard there'll be a balance part in the next patch, I'd suggest to look at that.

Interesting propositions