I've been reading the recent threads about BoE and scenario design. 
I've built three 'epics' so far (at least they are to me), and 
believe me, they take WAY too much time. The last one took me NINE 
MONTHS from start to finish. My advice to everyone out there: Build 
small, rich scenarios. To keep BoE alive, we need to constantly be 
providing new scenarios. The best way to do this with a limited 
number of developers is to have them produce more scenarios. Smaller 
scenarios take less time to develop and release, thus the same number 
of developers can produce more scenarios in a given amount of time.

When people have to wait two to three months between new scenarios, 
their interest will naturally wane. If we can provide new scenarios 
every three weeks or so, that will keep BoE alive better than 
anything else I can think of.

My next scenario will consist of two outdoor sections, and about 20 
simple 'towns.' But, I hope to make it my best yet by increasing the 
richness of the included experiences. I also hope to complete it in 
about one month, as opposed to nine.
Brett Bixler