Hmm... if you like fantasy and wargaming you might like Land of Legends, or Battle for Wesnoth...
Dominion, BTW, is very important - for one thing, if you lose all your dominion, you're out of the game. Perhaps that is how you won your game - did Ermor run out of dominion? Also, you were correct in thinking that it made your god stronger - it directly affects your god's (and prophet's) hitpoints. In a +10 dominion province your god will have triple his normal hitpoints - but conversely, don't send your god out into enemy dominion if you expect him to get in a fight!
Dominion also affects other things such as morale, too...