As I understood it, fame was supposed to tie together hero progression and empire building, so that you needed empire building to progress with having heroes.
At the moment, I don't really feel that fame is, well, famous, let alone legendary. One can quickly get to the stage of having too many champions, that one cannot field armies for (and in some cases, cannot even afford to pay) - getting a new champion often does not feel like an achievement, and sometimes does not even feel like a benefit.
I want to want fame. At the moment, it is a bit meh.
Suggestions:
New champions should always be useful; maybe an economic bonus rather than having to pay them.
Events should be triggered from high fame. Example - in the Bible, the queen of Queen of Sheba travelled to visit Solomon having heard of his wisdom (brought lots of gifts and trade). Magi from the east came to celebrate Jesus' birth (wait, more gifts). Surely in Elemental there are wizards, elementals and demons who are interested in a famous channeller...
Fame should go down as well as up - should defeats and dastardly acts should reduce fame?
Fame should maybe have economic benefits (keep things tied in with building the civilisation too). In Master of Magic, fame provided an army expenses reduction. Might something like that work here? Maybe even mana upkeep expenses?
Do people like fame as is? If not, how can it be better and more interesting?
