I voted good! This was a HUGE improvement over beta 3. Well done!
+ City specialization is a good direction. It gives the cities personality.
+ Fantastic job on the new interface elements. I especially like the new spell book.
+ Outpost upgrades were cool. I also liked the improvement upgrades being implemented with tile resources as well (like shards).
+ Essence is a good add. I think it has potential as a resource but it could be utilized more.
- Small map with 3 other AI players: The game play seemed to slow down considerably late game, not the graphics, the actual pacing.
- Magic started out feeling way too weak, but eventually (mid game) got up to acceptable levels. This will be tough to balance.
- Overall it feels like the magic system is a little detached from the rest of the game. Sure it modifies different aspects, but it feels. . . external. It seems like it needs to be brought up to speed with the rest of the systems with more meaningful interactions.
- Still noticed that one of the AI characters was getting astronomical mana spikes throughout the game.
- Pillar of fire will not kill, just bring them down to 0 HP and they keep on kicking. . . is that intentional?
- On the ledger, I clicked the 'Details' button for one of my cities, and nothing happened, so I pressed it again, still nothing. Three times total I pressed it with no effect, so I closed the ledger, and the Details screen popped up. When I closed it, another one popped up. Three details screens opened up in series after I would close the previous one.
That's all I can think of right now. Again, the concepts that you implemented this time for cities, outposts, and interfaces, were all positive in my opinion. Keep up the good work, guys!