Changed Spell:
Embrace of Elements = Fireshield + Windwall + Fair Winds + Waterwalking
Requires Air I, Fire I and Water I (the Water I requirement currently does not work i commented it out, once you add more promotionprereq tags just un-comment it)
Fair Winds and Waterwalking are made obsolete by Embrace of Elements
New Spell:
Exalted Defense = Wall of Stone + Inspiration + Hope
Requires Spirit II, Earth I and Mind I (similar to the spell above Mind I is commented out and the merged spells are made obsolete)
I am not a big fan of spells that simply merge 2 in 1. Especially Recovering Flurry looks odd since it basically removes Regeneration out of the game
I looked through all the spells and those two are the only ones that require living units and target their own stack/themselves (except for mutate). I tried giving the hasted promotion the <bPrereqAlive> tag but that does not matter when the spells says a promotion is applied it is applied no matter what the promotion wants (the only exception is unitcombat).
But look it from an other side it is still one less spell cluttering the menu, also having both spells separate really adds no tactical depth imho.
Here is a list of unused spells that could go together:
Affecting enemy units:
-Rust
-Maelstrom
-Slow (ice mana is too rare imho to justify merge)
-Snowfall (ice mana is too rare imho to justify merge)
Affecting enemy units that must be alive:
-Charm
-Wither
Permanent Buffs:
-Mutate (must be alive)
Limited Buffs:
-Lifeward
City Buildings:
-Wall of Force (Force mana is too rare imho to justify merge)
-Growth (Creation mana is too rare imho to justify merge)
-Birth (Creation mana is too rare imho to justify merge)
-Justice (requires Courthouse thus limiting other merged spells to this requirement)
Can go with any Spell:
-Dispel Magic
Summoning Spells:
-there are a lot however merging them would cause immense balance issues imho
So what are future possibilities (i could add them fast, but i am unsure if i should add them just post what you feel about them for example 1) yay 2) nooo 3) .... )
1) Dispel Magic + Rust + Maelstrom = Degrading Storm
2) Charm + Whither = Demoralizing Decay
3) including Life ward in Battle Preparation or Bravery
4) Mutate + Haste + Regeneration = Altering Burst
5) Including Dispel Magic in Sunrise (i actually don't think this is possible because of two python effects)
6)Shadwostep + Embrace of Elements = Engulfing Shadows
all names are pending of course, if you feel some could use a better one
if any of you have any further ideas feel free to add them, especially on how to manage summons (one way i thought of was a new spell: elemental horde it would summon a new unit which had the properties of all elementals combined (but not the combined strength ))
@sephi
in the files below i already commented out all things you already merged (disabling certain spells for esus and the already merged spells).