Ok, for a lengthier treatise upon this, see the other thread.
Most battle spells that are similar to realm spells have a far lesser duration and power. That’s like saying that charm person infringes upon mass charm because they both charm people.
No, it isn’t. The effects of the one is significantly stronger, and you don’t get it until you are much, much higher in level. In this case, the cost in terms of time and resources for casting a subversion or mass destruction is far higher than for casting a battle spell that accomplishes a similar purpose, and the net effect may end up the same.
While it may be true that higher level wizards can already be quite effective on the battle field, most wizards don’t make it that far. Thus battle magic is a way of involving all wizards in combat that doesn’t give them too much power for the cost.
So the argument here is, just because someone is not of a high enough level to cast a given spell, we’ll simply give him a lower level version of that spell? Since a 1st-level spellcaster can’t teleport, we’ll make teleport a first-level spell?
Also, not all wizards want to waste high-level spell slots on attack spells, many wizards prefer to use indirect spells, none of which can affect an entire unit (unless they move around in tight 40’ diameter balls, or 10x10 cubes).
It’s called “prioritizing,” not “wasting.” If you want to cast a spell, you’ll have to choose it over another. You don’t get it essentially for free just because you don’t want to face a tough choice. There are many indirect spells that can be hideously effective. Not every spell can be useful in every situation. If you happened to have prepared a cone of cold when what you really need is a teleport, or vice versa, then, well, tough luck. And military units do move in formation, you know. Often pretty tight formations.
Also, there aren’t very many wizards that exist, thus most combat is done without magical support anyway.
So then, why all this hassle about wanting special rules for those very few wizards?
As for battle-magic being cast outside of battle, why do you need to cast these kinds of spells outside of battle? If you cast them, you are usually in some sort of battle, where taking the long time to cast them has been determined to be neccesary to acquire the effect that you want. I guess you could put on some good pyrotechnics outside of battle for a big celebration, if you wanted.
Ummm. Because you can? I mean, isn’t that why wizards use spells in the first place? They use the best available tools for the job. It’s a pity they don’t always have the right tools, though. But a clever wizard makes do with what he has. Now. If you assume the existence of battle magic and such - it should be part of any wizard’s dungeon crawl repertoire. How about a battle spell version of summon monster? It’s in the book. Lots of cheap cannon fodder to keep the enemy busy, and no experience penalty (summoned monsters don’t have any effect on that, very clearly stated). You could cast this prior to a given encounter, and use it to clean house pretty fast. Why not a battle spell version of burning hands? Oh wait. That’s called a fireball. There are many ways the battle magic system can be broken by “creative” players, despite the attempts to prevent this in the BoM.
Want battle magic? Take a look at the War Magic cards - cards #94-100 in the Birthright box. These show how to adjudicate the effects of ordinary spells on a battlefield. There are a lot of spells there that causes significant battlefield effects. Your DM is quite unreasonable if he does not apply those effects. Adding another category of magic is just redundant cheese; especially so in a 3e environment.