Been enjoying the new DLC and 1.5 patch. Great work. In my last game, playing as TEC Loyalist, I was going for the Archeology achievement so I had built a huge 5 star map with only one AI. I conquered my system quickly and moved on and captured the other 3. During this time I only used a few planets with Social Improvements to spread my culture in these systems and focused more on industry and trade. The last system to conquer was the AI system but, like I mentioned, I was wanting a certian achievement and that meant focusing on the planets that had the Artifacts. So I prepped my fleets and struck at these planets first and used Social Improvements on all of them with 3 cultrual towers and having completed my achievement I got ready to attack the AI.
Except I didn't have to do much attacking. The 4 gravwells I had captured and upgraded and literally spread culture through the whole system. By the time I had the fourth planet with the last Artifact captured the AI had lost half of his remain planets to culture. I pressed on to the AIs capital planet and by the time I had that, had to go through two planets to get there, I had won the game as all the rest of the planets rebelled. Social Improvements make Culture a viable weapon, at least with the AI now. Love the new changes.