It seems that my people (particularly the caravans) are no fans of planning ahead too much: when I want to tell a caravan to go to a rather distant city, he simply refuses. No target cross appears, and he doesn't move. Initially I thought that there might be no connection (as still happens at the pass, between my first two cities in the Campaign), but when I teased him step for step along the way I wanted him to take, it worked out.
Thus: bug. Should be able to plan further ahead. After all, it surely can't be a time problem in the A*, right? 
Two suggestions:
1) When doing a quick save, a short confirmation (quickly fading) would be appreciated.
2) I found the Obsidian wall after sniffing around in the north (exploring the land, ignoring the ship and everybody else). The description said "The way west, for now, is blocked".
Why west? The wall goes east to west, thus only blocking North/South approaches.
Furthermore, I got this message for every tile I visited when walking along that wall to the east.
Finally, a buglet in the forum code: I have to write 1) and 2), instead of a) and
...
Ciao,
Klaus