Concerning the illusion arcana, I needed to explain what were these illusions. For me the illusion of an object is an artifical creation of light which imitates the object (obviously it's not solid). In so doing, the light is "real" and if camera would exist they would see the object.
I tend to prefer such illusions over "mind-affecting", although both principles could exist within the same game world/system. It still makes me wonder how many purely/mainly optical implications come with such a spell.
- Do illusions cast shadows? If so, an illusion would not just "create" light, but also "block" light. If no, I assume illusions to be slightly translucent - easily spoiled if the illusion is between a light source and the onlooker.
Lets say someone casts an illusion of four walls and a ceiling around me, with no (illusion of) window - do I see the inner walls of the "room", or is it pitch black "inside"?
- Do illusions really "create" light? Would an illusion of a torch illuminate an otherwise pitch black room?
- Do illusions reflect light? Could I create the illusion of a mirror, an optical lense, a knight in literally "shining" armor? Would an illusion change colour if it was not seen in white llight, but in colored light?
No clear preferences from my sight...only towards a more generic magic system, where illusion, darkness, blindness, light sources and so on are not different spells on a list, but rather possibilities within some kind of...uhm, well, magic continuum.
Edit: My problem is that while it might sound rather cool to have flaws to illusions - or rather magic in general -, I find it hard to roleplay because of player knowledge.
For example, I came up with the illusion of a tree that is perfectly symmetrical, or an object that seems to bee seen from the front even if you change angle and walk around it (like in early "3D" computer graphic based on bitmaps). I think those might be very conceivable flaws, within my game mechanics.
However I'm afraid that players will all too easliy conclude that it might be an illusion, taking this as a rather "mundane" explanation, since they "know" the mechanics behind it.
Well, having said that, I concluded to be less afraid, and in turn proactively foil such thinking ;-)
Like involving trees that ARE (or at least appear) perfectly symmetrical, but still are (or at least appear to be) trees, as far as any player can tell.