Hi there,
my apologies if this has been said before but I think the fact that the planet is revealed when you are about to plant a spy is IMO a huge exploit. IIRC in DL the planet was revealed only if you had reached a fairly advanced espionage level.
Now in DA you can reveal the planet straight from the beginning of the game by opening the "place spy" screen (Ok, you don't see the figures but you see what's o every tile). And on top of it, you don't even have to actually place the spy, once the screen is open, you can abort the procedure and move to the next planet to check it out.
This is surely one thing a human player can exploit while the AI most probably can't take any advantage of it.
Regards,
farkas