Personally, I don't often use tools at all. Tools are simply that - aids for the actions the mind is undertaking. I feel tools thus can be made of whatever resonates with the individual, whether it be 'natural' materials like wood, or human-worked materials like metals. Metals are, when all is said and done, still 'natural', as in 'coming from the earth originally'. We actually have nothing that doesn't originally come from the Earth, if one follows the chain back far enough.
For those who have been taught to use only particular tools for particular tasks, their beliefs may spoil a Ritual for them which is undertaken with anything else, however. It all comes down to what one believes, IMO.
I think it's largely up to the practitioner's preferences - what you believe will work best, or what makes the most sense to you, will be the best method.
That said, for me the wand corresponds with air and thus represents journey through the world tree, or the three realms (underworld, middleworld, upperworld). Being that the wand is associated with the world tree, I have made mine out of wood and painted the spheres of the qabala (just a more complex version of the world tree, if you ask me) on it. There's a picture of it on my profile page. I use it to invoke energies from the other worlds and invite entities to journey to ours, whereas I use the drum to journey to their worlds. So if I'm drawing upon and directing any energy that's not my personal energy, I'm using the wand.
The athame then corresponds with fire and thus should be metal, forged in fire and representative of the personal will. I use it to direct personal energy - creating a ritual circle, drawing sigils and other energy constructs, consecrating items, or charging an item with intent.
I don't have to use tools, and I've done ritual with and without them, but most of the time (depending on mood) I prefer to use them. To me it's like the difference between a teacher standing back and gesturing at the overhead projector with her finger, or rapping on the exact spot that needs your attention with a pointer stick.
I noticed your mention of the Golden Dawn associations for Air and Fire, and they caught my eye. I believe when Gardner first published, he switched those associations intentionally for people wishing to know about his Wicca, holding to the intent of secrecy. I felt from the first, before I ever knew much of anything about Gardner or Wicca or the Golden Dawn that the Athame belonged with Fire, and the Wand belonged with Air.
Fire destroys - the blade cuts - and both must be used with care and conscious direction. Air supports us and is necessary to us, and is invisible to us, as is energy, but both can be directed for positive use, while positive use still results simply from their presence. The presence of uncontrolled fire or blades handled or used carelessly can result in a great deal of destruction, and very little of positive benefit.
I agree with Jul that the Blade casts a tighter Circle, however. When I use tools to cast a Circle, I use Fire and Air, in the form of incense, then Water and Earth, in the form of salt water, and then use a Blade for the third and final drawing, to sharply define and 'cut' the Circle, symbolic of imposing my Will that the Circle be Sacred. I also use the Blade to 'cut' doorways as needed during the Ritual and to close them.
For me, both the athame and the wand are representative of the element of fire, and as such either one can be used for working with energy or for the art of casting and closing a circle. Where they differ from my perspective is that the athame, working with the will of the witch, is used to direct energy whereas the wand, working with the energy of surrounding forces, is used to manipulate energy. It is no surprise then that an athame makes for a tighter circle casting and a wand works better for sending healing energy, for instance.
I've worked with both metal, wood, stone, and bone wands, and don't have a preference for one over the other. For me, an athame should either be metal (forged) or stone, but wouldn't work as well with wood. In the end, it is whatever works for you, however.
Diferent materials are more or less conductive of energy. I think metal is very agresive in this sence, while wood makes more harmonic flows. Theorically the athame or a sword would be better to focus energy into a point, for example if you want to fill yourself with it you direct it to yourself with the blade, and ceremonial magic demands the circles to be made using the sword, so to both questions in the OP, i'd answer "Theorically the sword/athame is better". But the wand might be better, especially when you consider wicca magic is natural and harmonic than ceremonial magic. I think it's best to cast the circle using a sword, and if you want to focus energyinto a point, the athame might be better than the wand, but for any other task i'd use the wand.
Drakill, do you think it is possible that metal is 'more aggressive' because the Will of man has been already imposed upon it in the process of smelting and forging? I rather suspect that is true~ I do agree that wood is more harmonious, too. I feel it may be so because it comes from the living tree. Man does not form and shape it - we only decorate it to (again) harmonize with our purposes.
A very astute perception, Phoenix. We could also see the Athame as being more aggressive because we used similar shaped objects to kill. I know I would be more scared of a metal knife than a wooden one.
But on the other hand, Humanity's first killing weapons were probably wooden clubs and spears with fire-hardened tips - and then stone and bone came into use before metal. Anything can be used to kill - if that is one's intention. BTW - don't discount wooden knives - they can kill you as quickly as a metal knife can, if used for thrusting.
I think a lot of our perception is how we personally think of the knife - as weapon or tool. After all - we all use knives every day for food preparation, and they don't ordinarily make us think of killing...
My focus is on knives as tools. True, some of my knives are better fitted for killing than food preparation, but even for that purpose I consider them tools. Don't mind me, though - LOL! I have a serious fascination with sharp-edged, pointy things! LOL!! I have a wall full of them of various sizes and styles, and a drawer full of belt knives. Perhaps being a Fire sign contributes to my attitude toward blades?