Hmm, you may be right.
The current situation is due to a different set of desires and aims. I wanted you to repeatedly have to try to stop messages from getting out, so you have to pay attention and invest in messenger-assassination techniques. For some situations it works great. The fog I think is roughly balanced how I wanted it, but this means that the fishmen now have no solution to messengers on land.
Dark enthralled can transmit shadow at improved rates, so they're the best way to cheaply get rid of entourage, since they'll become broken within a certain number of turns.
I'll have to look into it a bit more, see if I can't balance things a bit better, maybe introduce a few new options. At the very least, I could make assassinations cheaper for entourage members, although that's not an ideal solution.