So I have just finished a few rounds of FFA with the AI on Nightmare difficulty and now that I'm used to the game mechanics and all the new features I'm not encountering resistance anymore. I basically get four to five planets, do some research while making some units, then just take over the galaxy. I do this by creating a medium size fleet and then taking a few extra planets. I then use all the surface slots to increase the garrison and max out heavy factories and hangars. I don't even bother with starbases anymore as they take took long to build and there is no enemy resistance
At this point in late game it's basically a runaway power situation. I have a million of each resource, hundreds of garrison troops, and a huge fleet. I know the AI is really dumb right now, so that is part of the reason. However, I so want point out some possible improvements: Research completion and ongoing cost, garrison ongoing cost, and resource availability.
I think the research needs to be much more expensive, and it would be great it there was tons more of it. I think that as you finish more research there should be ongoing costs to it so you don't just blindly continue researching all the way to the end. Similar to fleet upkeep in sins 1.
Same thing for garrison units. They are too easy to max out and keep you safe from everything. Make it expensive to just spam garrisons at every planet you take over and place heavy factories on them.
There are too many resources late game. The game is basically on autopilot at this point and there is no need to do anything but conquer planets. This ties in with the last points. When you have 40 planets it should be more difficult to manage all then drawing your attention back to keeping your planets "maintained".
Games looking really good.