That's pretty much how Infra Arcana's sanity system works...
Which is kinda funny, since there was a bug in IA that would crash game, when you reach 100% insanity. Guess not many players reached that state and just died long before that.
As for ideas related to wound/HP mechanic, soft/hard health points idea isn't something new, it was just executed previously a bit different. Rechargeable shield can serve as soft HP, were you don't take any damage, when shield is still on (typically small amount of shielding is provided and it is recharging fast). When it wears off, damage is done against hard HP, which often is not easily regained or not regained at all. This can work for some games and fit some themes/settings.
The problems starts, when soft/hard HP are affecting same resource as proposed by NON. As I see it gaining one wound would increase chance of getting second one and so on. Cap between not gaining and gaining wound would be lowered each time. Combined with the fact that Infra Arcana isn't easiest game already, in my opinion it wouldn't work.
Right now wound distribution is random, but flat. Chance of getting wound at low and high HP is the same. Penalties for wound are there, yet if need you can play few levels with wound in critical situation relaying more on other resources (using more ammo etc).