The game's been out for a bit now, and I've been on both sides of the table. As a player I tend to be accommodating to the GM, as a GM I tend to limit my house rules as much as possible to only those situations that will enhance the game or make my life easier. With all that in mind a have a few ideas of how I plan to do things in Gods of the Fall.
I used this in the play test I ran last week for "Thirst" the adventure I am writing for the CypherCaster and I think it worked well. It's less a rule and more a guideline or perhaps a "visual standard." Basically while a divine's aura is normally only visible to other divines (unless they choose to make it so) whenever these divines use an ability or power of their's (especially those linked to their domain) their aura will briefly flare and display itself for all to see. This helps to make the use of abilities a more dramatic and helps to reinforce the epic nature of the game. This was inspired by similar features in Exalted and Scion from White Wolf.
Because it didn't matter for the playtest I didn't offer it as an option but I would consider allowing players to hide this flare by expending a level of effort or raising the difficulty of the roll by 1 level when they were in a situation where the difference between displaying a divine power and an (apparent) sorcerous power would be beneficial on the character (for instance while operating in Corso).
I'm on the record (somewhere) as a GM who separates advancement XP and GM Intrusion XP at the table. I have found that there are some players who will hoard XP and suck up whatever misfortune goes their way to advance more quickly and others who will bankrupt themselves for a chance to re-roll at any time. I know that that is player prerogative, but I find that when you have players who begin to slip forward or backward more than a couple of advancements things can get a little weird, and given the nature of the characters and the swinginess that can be present in Gods of the Fall because of divine shifts (more on that in a future post) I am simply going to go one step farther (further? I never get those right) and do away with advancement experience entirely.
Instead I am going to take a cue from Shadow of the Demon Lord and simply dole out advancements at the end of adventures and story arcs as rewards directly. I'll still use normal XP rules for GM Intrusions and those can be used for Immediate, Short, Medium, and Long term awards normally. I'm just going to do away with any kind of end of sessions XP in favor of directly awarding advancements.
This is less of an house rule and more of an explicit allowance of an uncommonly used optional rule (at least in my experiences). Basically I plan to make it known that players are both welcome and encouraged to use the "Modifying Abilities on the Fly" rules from the CSR (pg 226) so long as the modified effect falls within their Dominion. I'm not going to allow a God of Death to try and modify a fire blast into flight very willingly, but if they want to use the same fire blast to "soul burn" (and bypass armor in the process) I'd be much more receptive. The way I see it, the gods are masters of their domain (*ahem* Seinfeld references notwithstanding) and should be able to perform stunts and epic style feats within that domain's purview.
What house "rules" do you think you may use for Gods of the Fall to help set the tone and scope of your games?