First, a semi-ranty-ish question: Is there any reason behind the ruling that a holy symbol can be made of wood (weighing nothing), or silver (which means it suddeny gains weight; one pound to be precise).
Hmm... so if I don't want to take the El-Cheapo variant, I get stuck with a lodestone around my neck (last time I checked, pendants were considerably lighter than a pound... and if I need something dramatically appropriate to shove in evil's face, a wooden thingie isn't exactly weightless, either).
Next question: Since (as least from what I read) engravings on your shield or armor, holy weapons, certain tattoos and birthmarks (as per the trait) all qualify as 'holy symbols', does the symbol have to be openly visible while I use it? (Which would put quite some limits on the applicable locations of a tattoo). Will the symbol shine with power when used as a focus? (Can't find a rules entry about that, though I'd consider the visualy to be rather fitting, I must admit)
So many questions...