What physical properties do you want in Filament

Thought this would be an interesting question to ask the community. Who knows, maybe some filament manufacturers are listening.

What physical properties do you want in filament?

Here are a few I'd like to see:
- conductive filament (using a dual extruder could allow us to print complete electronics parts)
- color changing filament (not sure why this isn't out yet) - a filament that changes colors based on temperature
- camo filament - filament that changes colors based on its surrounding (I know, this seems impossible, but I think one day we will see it)
- more filament like Bronzefill (from colorfabb) where it has enough metal in it that it feels and looks like metal.
- sandy-like filament - a rough and touch surface where you could almost use it as sandpaper.

Let's hear yours

High temperature PLA, I believe it is the best all around filament from the point of view of ease of printing and environmental impact, both in the outdoors environment and the indoors, there's no toxic fumes like with ABS for example.
The main problem with PLA is that it gets soft at around 60C, just 15 or 20 degrees higher glass transition temperature would be a huge improvement since those are not temperatures that can be found in a normal environment.