It lost the 10% building and district upkeep in exchange for 5% build reduction and an additional building slot. The 10% upkeep reduction was very powerful because it applied to everything, including things like the strategic resource upkeeps of resource boosters. It was also boring because it just kind of existed in the background and you never interacted with it directly. +2 building slots and -15% building cost reduction is something you see immediately and is very exciting, even though in all non-habitat situations it's something you could eventually get just by building a couple of extra cities.Agree. These sweet +2 building slots are too addictive, making colony rush so comfortable. And megacorp private colony ships will save even more resources on colonisation.
By the way, I really don't understand why this civic was buffed from +1 building slot to +2. It was fine even with +1. It is the only thing that I can't get in the last balance patch.