AI: do things for connectivity
alain_bkr Simple tactic may be good enough Just one strong defensive (2) unit fortify, with one worker Then just move both to next tile.
I rarely lose my units, because the fortified unit often survives the first attack, and sometimes the second one. So it is still worth the trade, lose two cheap units versus opponent lose 2 expensive offensive units.
my 2 cents
A consequence of a number of patches, mainly #45946. If roads between cities get important, AI should have an idea of making them. The problem is that the builders (and the trade ways, while it's still future) should be guarded. The guards could be units with high defense to mop up the attacks or with high speed and attack to kill the attackers on approaching, and in a good case we also are not omniscient and need scouts patrolling the perimeter; maybe a tower should be built for them?.. Probably we need a danger estimating function like "how many enemy units of each type will strike tile X if we put value V on it and the density of our units around is...".