Well. I do still think that Prestige should be a little bit more variable than just a few buildings you can build. I like the Soverign attributes you can use to tweak around Prestige, but I wish there were more of them.
- Cities that you captured of a different race having a lower prestige, especially if you go to war with someone of their race.
- Cities with low or no defensive fortifications have negative prestige. Cities with large standing armies have positive prestige. (this is a way of balancing the currently rather-high upkeep cost of units).
- Cities with trade caravans get a 10% increase in their rate of prestige per trade route.
- More improvements seeing a prestige modifier. Smaller, but some plus, some negative.
- If a city has to "import" food, it has a negative prestige (speaking of which, it would be nice if there was some way to "disrupt" caravan routes to prevent the distribution of food)
And so on. If Prestige is supposed to be an important mechanic, there should be lots of ways to play around with it. More than just "build Temple, get 1 Prestige". It's the same problem that Essence currently faces. It's an important mechanic, but it's not well-enough developed in the character screen, and you have to be very very careful with its use (which is totally fine... but a caster-type Sov needs lots of mana to cast, which means he can't freely expend his Essence on other things, but a more warrior-type Sov can spend or imbue most of his Essence without too much of a worry).
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Also, will we have a "Steal Essence" from your champions? Get a Caster Child, and take his 3 Essence to your 1? It would be a natural way to generate more Essence as the game goes without endangering your Sov too much.