(Without refering to Azerty's links, so may be copying/restating things inadvertently...)
Initial additional thoughts of some of your initial items.
Ardent worshippers I mean. Currently ardent worshippers of death gods become necros.
AGRICULTURE
Performing prayer has a chance depending on performance quality to make nearby vegetation receive randomized bonuses to growth speed and durability. Has a randomized cooldown at pair with rolling a divine dice. Passively prevents worshipper from breaking vegetation if he doesn't have this trait already otherwise chance for growth will always be as high as if speech was masterful.
Could be, at a high level, even be "footsteps of flowers", (semi-)instagrowth of compatible vegetation (sporadically?) wherever they have stepped. Not trees, but otherwise harvestable of course.
BLIGHT
Immunizes creature specifically to necrosis and makes vegetation around you forcefully receive poisoning. To prevent it from being overpowered it only happens on full moon. Very quickly becomes enemy of own civ if refuses to leave. Exile is nearly guaranteed. Capital punishment may also be tried to be landed but "convict" may escape. Weakening plants won't work on vegetation blessed by AGRICULTURE deities. Such creatures, if they still worship their deity responsible for it may try to wander around and spread the blight.
Obviously I'd suggest "poisoned footsteps" as a counterpart of the above. Where paths cross/coincide might force evil-biome plants, even/especially where not usually possible?
BALANCE/CHAOS
- respectively create far less/more extreme variance in random physical (magnitude) stats, of some kind? (Either of self or of those persons/creatures encountered.) Although I'm not sure how to make this necessarily a worshipper 'bonus' of some kind, as they both should be (give or taken).
((PPE: Snipped a lot, probably not even as well formed as my above suggestions weren't. You don't want walls of text explaining why I think SPHERE_X and SPHERE_Y are directly complimentary to each other, just for the sake of it.))