I have just recently read about 2 new filament's, one is anti-bacterial like you said (there is a competition for it on MyMiniFactory currently) and also another one on this same forum about a super conductive filament. I think the problem with heat-resistant to a point is, we need to heat it up to print with it. So that's going to limit thing's to current desktop printer heat's. Transparent filament's keep coming out better and better, I just bought a sample of the new HD glass from FormFutura, it's pretty transparent, not "glass" not it's probably the best I've used yet.

I would like to see more metal-based filament's that have great post-process option's to them. I would also like the price's of those filament's to come down in price :P Also, a legit wax filament would be really useful.