In my last game, Verga had cast stoneskin on himself enough to have a defense of 80, 8-12 times.  Later in the game I bumped into him again with a defense score of 60, he had stacked it 6-8 times.

I found out that each hero with tireless march stacks.  Was a fun find, but I'm not sure it is as planned.

 I played a game as Tarth, I would normally avoid them.  With their movement bonus in rough terrain and the Enhanced Bows, I had a really fun time with mounted archers and cavalry.

In that same game I was griefed for a while by 2 Obsidian Golems.  They sacked my best fort, but in the end the only thing left of them were their (midnight) stones.  They were apparently on leave from the area where you rebuild the city.  One of their original camps yielded a Lightning Bow,  Irane was a bad ass with that.

More of the wildlands bosses need to be challenging with 7-9 man units and 20+ Hero's  (I know that has been mentioned before)

Verga displayed some sound judgement at one point having disappeared for a number of turns and reappearing at a weakspot in my defenses.