Really? Hegemony being harder than GOLD? I dont think that stands correctly..i believe gold is harder.
Vanilla(as you say) : When lose units, they regenerate fast at the cities, ready for battle again. So that means, if you inflict big damage on your enemy, they will be ready again very soon. And so will you...that means, you can keep conquering enemies, and outnumbering them all the time!! Thats what makes it easy!
Vanilla has a hard global cap on how many units you can have at any given time which, at times, makes it more difficult to muster enough troops to carry on with your campaign and defend the conquered lands, especially non Macedonian. Also elite Macedonian units once routed have a long walk home and back before they are at the front lines again, especially later on in the campaign. With new "home city" mechanic you could change their home cities very close to the front lines. I have not tried this yet because there is no need. I have yet to see any of my Macedonian Hoplites or Phalangites rout which makes moving of home town unnecessary. Even on expert difficulty.
Gold : Each city has a pop cap, where units regenerate from that cap. The cap is small in most cities, so if you make one mistake in battle,it could take hours to regenerate. That means, its the same for the enemy too!!! But if you conquer an entire nation, its takes more time to heal, but your NEXT enemy, is already full..thats what makes it harder, you can make many enemies at one time, without realizing it!!
Gold has a max recruit pool per city which replenishes itself indefinitely and in theory grants you as many units per city as you can pay for. In this case gold is the cap, not population of any kind. This is what AI does as I mentioned in my original post. For me as a player it presents you with two options: fast after battle recovery if you keep your recruit pool full at all times or more units from same city, say Phalangites.
Due to the slow speed at which recruits are replenished in the cities once you bruise and route most of enemies fighting force, they have no chance of stopping your advance. The routed units are not enough to man the walls and cities fall without any fight. I have taken whole swaths of land this way while fighting my way to the east. Beat the main fighting force in to a retreat and the rest just folds like dominoes.
Lack of any enemy raids makes GB-10 even easier. I really don't consider the amount and frequency present in this beta to be anything more than nuisance, never mind a threat.