Currently a Satraps recidence, and the buildings of that same types gives happines, wealth and eastern culture. All these I think are good, though there is a minor change that hopefully can be done. A satrap was like a local king appointed to administer to a certain region. It allowed for the locals to have rulars of their own kin thusly lowerig public unrest. What doesn't make sense though is that the building only spreads eastern culture where ever it is placed. I suggest they should instead spread the local culture, you know the original culturee, or local traditions. So a satraps recidence placed in armenia would spread eastern culture, but if placed in greece it would spread greek culture. This will not only lead this building type to make more sense but also to help create the seleucids into a truly multicultural empire and not just Greek and Eastern Empire...

I hope this is possible, though I now there is an edict celts have where they can lower some costs by allowing local traditions to grow...