Disclaimer: I am not sure if this is a bug or intended but because it is a massive change and i have not seen anybody mention it I thought I start a discussion about it.
In update 3.1 the reduction to construction time has been removed due to the introduction of "Rush Construction" as stated in the blog post. However the reduction to global construction cost and the boost to income from all buildings is also removed even though the different tiers for the slave amounts still exist. In the picture shown this would have been -25% construction cost and +20% income from all buildings at 10k+ slaves in 3.0. Now it only increases control at low slave levels and decreases control at high slave levels. This is a massive nerf for the dark elve economy!
In update 2.2 the slave system was changed so it is beneficial to have high slaves because it boosts income, lowers construction cost and reduces construction time at the expense of a decrease to public order for the different tiers.
If this is a bug it should be hotfixed as quickly as possible as it has a major impact on the whole race.
If this is intended I do not really understand the change and do not really agree with it. In my opinion a good game mechanic should be a dilemma with pros and cons. For example have high slaves and a strong economy at the cost of control or have low slaves but therefore lower boosts and higher control. Right now there is no incentive or upside at all to have a high number of slaves because there are only drawbacks due to lower control therefore it is best to always have low slaves and get the control boost. It should be similar to the chaos dwarfs where you want high slaves for your economy at the cost of control and you need to manage it.
In my opinion incentivising the player into only one play style is a bad move because it takes the strategy out of a strategy game.
I would love to hear other peoples opinion on this!