What is the intention of the good faith rule? Is it to allow cards to function is certain situations where they may not normally work due to specific circumstances, or is its purpose also to allow cards to function in all circumstances?
There are some cards, such as No Hiding Place or Burn it Down, that work within the rules framework (ie they function whilst you are opposed), but in certain circumstances do not function but for the good faith rule (eg no opposing units). Whilst it can be argued that a change to the rules would allow these cards to function (eg cards not needing to meet required targeting would allow a ranged attack to be announced before playing one of these cards), I accept that AEG have chosen to use the good faith rule to cover this situation.
In Ivory edition, a number of cards require the good faith rule to function in every situation where a player want their effects to resolve: essentially the cards do not work within the framework of L5R but for the good faith rule. Examples of such cards would be those that have an interrupt that the player has to trigger whilst the card is out of play (Jade Pearl Inn, Kitsune Kichi experienced Kitsu Tamao etc), or an interrupt that can only be otherwise announced due to good faith (Secluded Outpost). When cards could be worded in such a way to avoid requiring the good faith rule* (or given a keyword that would allow the same**) it seems slightly awkward to instead lean on the good faith rule to allow these cards to function. Does the good faith rule allow cards to be written in more-plain text for an intuitive understanding? Everyone knows what Secluded Outpost is meant to do and so a simple wording plus good faith is better than a more complete wording?
*For the example of Secluded Outpost: ”If this Holding bowed to produce Gold to Recruit a Personality…” vs (I think) “If this Holding bowed to produce Gold and the action recruits a Personality…”
**For example, Jade Pearl Inn etc could have the ‘Province’ keyword to allow the interrupt to be announced whilst face-up in a province, or ‘Out’ (or a less-horrible name) to allow them to be announced from any out-of-play location.