Thanks to the 1.9 Map-size Kerfuffle I've finally been giving an Insane map a try. I guess I just doubted that my semi-serious rig from two years ago would hold it up well, but it is so far playing well. Loading saves and processing turns has gotten noticeable now that I'm nearing turn 300, but that's only because they are so blazing fast for me these days even on my usual pre-1.9 Immense maps.
So I'm not sure if what I think I'm seeing is an AI 'weakness' or more a reflection of how differently an Insane map with tight clusters plays and AIs on Normal.
My question is: Why do the AIs seem to be almost completely ignoring those immensely valuable resource nodes? My Snathi Revenge neighbors declared war on me 50-100 turns ago when they had a slightly better infrastructure, a vastly larger fleet, and we were not far apart tech-wise (or space-wise). I had already secured maybe 10-12 resource nodes and spotted two unused ones down in their area.
At this point, after some proactive aggression on my part, I've taken around 20% of their territory, more than doubled the resource nodes that I control across a scant third of the full map, and found yet another unused node right beside Snathi-controlled space.
(On the up side, they seem to have done a better job than I've seen so far of using starbases to get warships close to my worlds.)