Good point, I'd forgotten about that. So the ward wouldn't see any benefit from the original threshold unless it was blocking magic, whereas a ward CAN block non-magic too.
Hmm, so scrap what I said earlier, I didn't understand it properly. Thanks forum
*blushes* So let's see if I've got this.
So the threshold just stops magic, and hurts or weakens any magical creature/construct/effect that crosses the threshold without being invited. Any spell or mindless magical creature that tries to cross may be instantly dissipated if the threshold is high enough.
A ward can be (and almost always is) placed with a threshold. It can prevents anything crossing, whether it is physical or magical and it automatically targets everything unless specifically cast with added complexity.
A magical creature/construct/effect will be blocked by both the threshold AND the ward at the same time and I don't think one would replace the other so I would personally combine that block in to one MEGA block (it'll probably be just a couple more shifts). However they wouldn't combine in any other way I imagine.
Make sense?
I can't see why a +0 threshold wouldn't be usable for a ward, it's still there.