Ages in Dominions III is complicated and all-encompassing---really you'll just have to dig into some wikis and/or get the game to fully see how it goes. Types of Magic, Pantheon at play, Civilization styles, Nations, Conventions of Warfare, etc---it is a hallmark of the game. Also, my memory sucks, it was Elysium III, the new one.
http://www.shrapnelgames.com/Illwinter/DOM3/DOM3_page.html
On topic: Nifty doings on the skill trees----versatility is key on those as opposed to railroading. Most games force a start at a certain place as opposed to letting you get to it in whatever increasing order you choose and it just sucks a lot of the variety out.
I am entirely rushed off my feet at the moment, but once I get a spare day I'm going to do some serious research into these games, as well as a far others other people have suggested; it all sounds very interesting. On skill trees, I totally agree; in URR you have to start at the centre of each skill tree, but nothing else is determined apart from that. Similarly, the cost of skills only goes up per tree, not as a whole, so at any point you can start a new skill tree and get moving on it - I wanted to avoid games where gaining skills really slows down towards the end, and your ability to change your style of play lessens. There WILL be a limit on how many trees can be active at a given time, though, but I think I will allow you to disable/enable trees and thereby switch around which ones you have active, as that strikes me as an interesting mechanics that wouldn't limit the player's style changing through-out a game. There are 12 trees per era; at a rough guess, you might be able to have six active at any one time, with a turn-timer delay from the last time you changed them (say, you can switch one tree to another every 500 turns, or whatever).
MEANWHILE, a new blog entry! With lots of words, and no pictures. The next entry, however, will have lots of pictures and few words. Such is life.
http://www.ultimaratioregum.co.uk/game/2012/09/04/pretentious-gaming-talk-i/
