First, much thanks to the dev team for delivering such an awesome game with consistent improvements to AI that makes the single-player experience challenging and rewarding!
I say all of the following knowing that the Crusade expansion may change many of the planetary improvement dynamics.
But under the assumption that there will still be adjacency and that there will still be bonus tiles, I think it would be helpful to revisit the AI behavior as it relates to bonus tile usage because something seems to be causing the AI to regularly (about half the time, from what I've seen) place what should be adjacent improvements on the bonus tiles.
After acquiring a number of planets over the course of several games in the latest 2.0 release, I've noticed a possible trend in AI behavior regarding improvement placement. It seems that fairly often, the AI places an improvement on a bonus tile that matches the adjacency bonus of that tile rather than the placement bonus...
On a tile that gives a bonus to tourism and an adjacency bonus to research, the AI built a research improvement.
Now, I can understand that early on, before tourism is researched, having a research improvement on this tile would be fine--to a certain degree.
This quirk is not, however, limited to the tourism bonus tile. I've seen it on all of the different bonus tiles--sometimes with good cause but more often it just seems random.
In the layout above, however, one smarter layout would have involved placing a manufacturing improvement on the tourism bonus tile, grouping all three research centers together (a total of +6 adjacency bonus rather than +3), and placing the farm by itself on one of the lone tiles in the Americas. Then, when tourism became available, either deciding to place the Port of Call on the bonus tile or on the other lone tile in the Americas--favoring another research or manufacturing improvement where the Port of Call was placed.
Alternatively, to maximize the bonus tile, the AI could have placed three research buildings above the capital and six manufacturing buildings on the spaces to the right (Russia, China, India). Then, when tourism became available, they could have replaced one of the research buildings with the Port of Call.
The AI does regularly use the bonus tiles, and I think that overall, they are pretty good at placing improvements.
Has anyone else noticed this particular behavior or other issues with AI placement of improvements?