There are a number of interesting points about spell guidelines in the ArM6 thread. I want to explore the subject in a bit more depth so I'm taking the liberty to spin off a new thread.
First, Cuchulainshound makesan important point with which I thoroughly agree: to paraphrase, the spell guidelines are quite vague and it's hard to know exactly how versatile a spell you can make based on each guideline.
This has actually bugged me since ArM4. I have my own interpretation for how to deal with it, but YMMV. What I would really like to see is the guidelines rewritten to be more clear on how flexible a spell you can make. For example if you invent a CrHe spell to conjure a wooden tool, which I figure is approximately like the level 3 guideline (YMMV), I would prefer the guideline to say something like "create one specific type of crafted wooden object, such as a mallet or a bowstave" or "create your choice of any crafted wooden object," depending on what the designer's intention is. In the ArM5 rules, the language is ambiguous.
Now in my opinion formulaic spells should always do one thing only, decided at the time the spell is invented. So for the spell guideline, "turn a human into a land animal" (Base 10) there is Shape of the Woodland Prowler, which turns someone into a wolf. If you wanted to turn someone into a pig, that would be a different spell (in fact, it is: Curse of Circe). However if you apply that standard to everything it makes illusions pretty useless. And there are probably spells whose effects are much more flexible (Noble's Parma -- I am too lazy to look for them, correct me if I'm wrong).
All of this can be solved I think by the ArM6 designer(s) figuring out how general or specific individual spells should be, and writing the guidelines to indicate the specificity or generality of the effect.
There are also some spell guidelines I think are just out of whack -- it is too easy IMO to destroy stone, fly, teleport, or turn invisible, and too hard IMO to conjure a woolen cloak or re-attach a loose horseshoe.
So I put it to the community -- what do you think could be done in ArM6 to improve the spell guidelines?