I admit that I haven't been very good about making changelogs, but I think that my civilopedia actually explains things much better than that of Base FfH2 does.
The fact that the Desert Shrines give free promotions is actually pretty well documented in the building's pedia entry and its mouseover:
TXT_KEY_BUILDING_DESERT_SHRINE_HELP said:
Provides disciple units built in this city with a free promotion pick for every featureless, unimproved desert tile that the city is capable of working
The Desert Shrine code:
As you can see, the radius is three, but the line
if city.canWork(pLoopPlot): means that only tiles with radius of 2 would matter unless the city also has a City of a Thousand Slums or is owned by a Sprawling trait leader. I believe the tile also must have some yield, which unimproved deserts normally would not except for a Malakim player.
The Drown spell clearly has the Necromancy technology prerequisite stated in its mouse-over text and its civilopedia entry.
It is not my fault that Kael set things up so that the spell buttons do not appear and so their mouse-overs cannot be viewed until their prerequisite techs are known.
River of Blood does not have any technology prerequisite, in the latest version at least. It does require the Vampire promotion though, which would require waiting until Feudalism for any unit but Losha Valas to acquire. If you cast the spell before you had any vampires then you would miss out on the 2 free xp per vampire per enemy city that has its population reduced.
The Gift Vampirism spell has this in its help mouse-over/pedia entry:
Allows a living unit of at least 6th level (or 4th level if a Moroi) to take the Vampirism promotion. It may also grant Body, Death, Mind, and Shadow spell sphere promotions based on the mana you control.
Since the help mouse-over/pedia entry automaticaly mentions adding the Vampire promotion, I just changed the text to say this:
[ICON_BULLET]May add [LINK=PROMOTION_BODY1]Body[\LINK], [LINK=PROMOTION_DEATH1]Death[\LINK], [LINK=PROMOTION_MIND1]Mind[\LINK], and [LINK=PROMOTION_SHADOW1]Shadow[\LINK] sphere promotions, based on mana[NEWLINE]
[ICON_BULLET]Caster must be a living unit of at east level 6, or level 4 if a [LINK=UNIT_MOROI]Moroi[\LINK][NEWLINE]
[ICON_BULLET]Requires either a [LINK=BUILDING_GOVERNORS_MANOR]Governor's Manor[\LINK] or a [LINK=PROMOTION_VAMPIRE]Vampiric[\LINK] unit on the caster's tile
I just noticed that the Kuriotates world spell Legends still falsely claims that it adds culture to all your cities. I just now updated it to match its current effects:
TXT_KEY_SPELL_LEGENDS_HELP said:
Spreads The Cult of the Dragon to random cities and units
Moves the Cult's holy city to the caster's location
I also just updated the Cult of the Dragon pedia entry to make things clearer.