Exodus is exploring several things that occurred at the very end of the last campaign (Thule's gold).
The gods picked were not particularly good choices. Some were completely unsuited for the power.
Gods came to power after centuries of no gods. People have forgotten the purpose of religion so re-establishing religion as an institution is a challenge. The gods need to learn the rules of power from scratch with no guidance. Besmira as titan is a source of knowledge but she was given the domains of darkness and evil. So it is unlikely that she will shed light on the powers if she is true to her domains. This was yet another bad choice by the head of the pantheon. Luckily she was also given law and so Besmira can lay down a new set of rules that are not as poorly thought out but that requires usurping leadership of the pantheon. If done elegantly enough it should be obvious that Seldion does not have the wisdom to rule.
Besmira's rise in power has interesting implication for monster races that were associated with titan when they last walked the earth. Many of these monsters have been marginalized by humans but Besmira might give them a rallying point and a focus to rally around. What does that mean? What voids can they fill?
The elemental lord of Earth was destroyed. This has implications for the dwarves as a earth affiliated race. The new god of earth was also stark raving mad and given a bad set of domains for healing that damage.
We are also going to evaluate a number of class options from the non core books to see how they work and feel.
Several changes affect races in interesting ways. Racial powers have been tweaked as a result.
Considering it is a one-shot that is more than enough material. Main elements explored explicitly will be the following:
New gods : and the disparity between truth and belief
Heralds : how do you start religion from scratch with nothing to model yourself upon?
Dwarven Exodus. nuff said.