Mezzer said:
For everything else that wasn't a wraith.
Double their hit points too.
Mezzer said:
For effects which care about bloodied.
What does that have to do with anything? If a wraith has 40 hit points and takes half damage from all attacks, then it will be bloodied after taking 40 (halved to 20) points of damage. If a wraith has 80 hit points and takes normal damage, then it will be bloodied after taking... 40 points of damage.
Mezzer said:
This is a legitimate concern, but I have a hard time believing it's common enough to justify the nuisance factor. Just have all PC abilities that turn you insubstantial include the special effect, "You take half damage from all attacks."
Likewise, for effects or abilities that negate the insubstantial bonus, change them to "Inflicts double damage to insubstantial creatures." Instead of having a sweeping rule for all insubstantial creatures, have a specific rule for the oddball cases.
Mezzer said:
For a million other reasons...
Such as?
(On thinking about it, I guess it boils down to this question: Is insubstantiality something that mostly shows up as an innate monster trait? Or is it something that mostly shows up with normal creatures that sometimes turn insubstantial? If the former, then the half-damage effect should be changed to double hit points. If the latter, then the half-damage effect is the best way to handle it.)