With the removal of guild leveling in WoD, i think some customization can be done.
What about a talents panel for guilds? Like current class talents but for guilds.
Maybe the old talent panel (with point by point increases) fits better that the current:
Tier 1: Fast Track (1,2,3,4,5) - Mount Up (1,2,3,4,5) - Honorable Mention (1,2,3,4,5)
Tier 2: Blizzard Idea A (1,2,3) - Blizzard Idea B (1,2,3) - Blizzard Idea C (1,2,3)
Tier 3: Mass Resurrection - Mass Summon
With this, guilds will have flavors that players con choose.
Obviously, the guild master can change those talents (with the consensus of their member of course).
That kind of is what the idea of guild perks started as way back when they thought of them in Cata. If they are getting rid of guild perks (baking them into the game experience for the most part), why would they bring this back? Also I think the reason this type of iteration wasn't implemented is because let's face it there would be only 1 good option at any given time for a guild. If you are leveling guild choose option 1, if you are a raiding guild choose option 2, etc..... Blizz stated it did not really add any choice or thought to the game, and I agreed with them then and still do. Not a fan of this idea.