First, the
original is well worth reading.
Does anyone have any additions?
To stop the world
Spies. They are annoying little buggers that can hamper your enemy's economy. They can be much more, though! Imagine a group of 6 spies. They stealth through enemy lands, find his capital - and in one turn, cause over 100 points of unrest. No more sacred troops for you! No more capital-only mages for you! No more income for you! Even better, to catch the spies, the target of this strategy has to patrol, which reduces unrest, and as long as the unrest stays high, it's hard to catch any stealthy units, and he it will often take a turn or two to bring suitable patrollers. Once he has brought the patrollers in, you can move your spies out and wait until the capital is empty again.
Fearful Symmetry
Fear directly lowers enemy morale, as is easily noticed if you click on enemy units surrounding your Prince of Death. Heavy Cavalry with morale 4 are rather absurd sight... But, besides making it easy to rout them, low morale is also very effective protection if you happen to have Awe. Dominion values of 9 and 10 gives Awe, and I'm sure you all see where I'm going... Fear and Awe alone won't keep a unit alive, but you'll be fine if you add in some protection. Prince of Death can wear Black Plate armor without being fatigued by its encumberance. There are many, many ways to build an effective early expander around this idea, from Gorgon (med-to-high Earth for extra protection) to more monstrous creatures like Wyrms.