We need to have some real discussions on how realm and battle magic work and relate to each other. IMO we need to define some of these at least at the conceptual level since they affect both the war and domain chapters as well as the magic chapters.
This is my take (opinion) on these topics put out for discussion.
Battle magic:
Battle magic should be limited to spells that affect the battlefield or individual unit(s).
Duration should be in terms of battle rounds, singular or multiple.
Any spellcaster should be able to cast battle spells. They should not have to be blooded to do so.
Battle magic should be a variation of the standard magic system. That is battle spells should be an application of standard spells. We can create some new ones if necessary, but IMO we should make every attempt to keep to standard spells. If not then we need to include battle magic in the number of spells a spellcaster can know (e.g., sorcerers and bards) or learn automatically at each level and then deal with the number of spells he can cast in a day. Although I don’t think this latter one is that big a deal due to the time period, battles take place over days and weeks vice a normal combat round. This is something we have to work in the war section that will have an affect here.
The various mass spells in the PHB should be addressed as to how (and if) they have an effect on units. IMO most of them do or readily can.
IMO the application of the battle caster feat is as follows. A caster with this feat can target spells on a battlefield such that they gain the most effect from them. The caster has such control over his spells that he can distinguish between a friendly and opponent unit.
The various mass spells can work outside of the battle itself without application of the battle caster feat. For example cure moderate wounds, mass would enable a caster to heal the damage a unit took if cast outside of battle. To heal a friendly unit inside of battle requires use of the battle caster feat.
Realm magic:
Realm magic affects provinces and areas larger than a battlefield.
Realm magic may have durations longer than battle rounds, usually in terms of months or seasons.
Only blooded spellcasters can cast realm magic.
Realm spells are only researched not learned automatically with level or from spellbooks.
The maximum number of realm spells a character can know is limited by his ranks in spellcraft. (exact detail can be worked out).
Researching a realm spell takes domain actions (length of time depends on the ‘level’ of the spell).
A character makes a spellcraft check to see if his research is successful.
Casting a realm spells requires access to a source or temple holding and expenditure of RP and usually GB.
Casting time of a realm spell is a domain action.
Realm spells are not contained in spellbooks they are intimately known by the caster.
Realm spells are all unique and even if 2 casters know spells that have the same effects they are both unique spells.
Things that need to worked on:
What type of effect battle spells have. Should we continue down the path of the playtest and keep the results relatively simplified or list every spell and how it can have an effect on the battle? Or should we keep it simple (e.g., like the playtest) and only specifically address the effects of the mass spells?
How should we levelize realm spells? By caster level, by holding level, by a combination?
What type of saving throw system should we use for battle spells?
What type of saving throw system should we use for realm spells?
How many casters does it take to cast a battle spell?
How many does it take to cast a realm spell?
How many editors does it take to screw in a light bulb?