My thought of a SCH 2hr ability
I pointed this out before...
Job Ability: Mix
Duration: lasts for 1 min or until you mix 2 (can be 3 if SE wants) spells
The input spells: The input spells could be whatever spells that character knows with sub job. For example your on SCH but you've got /BLU spells on your character.
The Output spell: The output spell would be a ??? spell that the SCH creates. Some mixes may be offensive, some may be defensive, some could give the party an edge, some could hurt the PT or SCH w/ a side effect.
To make things fair the ??? spell can not be enhanced by stratagems. These spells have their own effect incorporated in them. For example "Barthundra" + "shockspikes" would be a positive Mix to create "lightningeater." Being that its a WHM aoe bar spell it makes it AoE however, the duration of the spell will be cut in halve. If the spell was RDM's "barthunder" spell it would have a longer duration but single target.
And to answer the question "Will the spell be castable on others even though its not AoE?" Yes, but some spells will be, some will not.
This would give SCH a vast amount of new unique spells. The only problem is it would be a 2hr still.