I'm getting ready to start up a campaign in January and I wanted to add some spice to combat to make players more invested. I've listened to people talk about L5R and other systems (I think GURPS also) that have interesting mechanics that address this, already built into the system. So this started me thinking about house-ruling something for Pathfinder.
I thought maybe something simple such as when a PC reaches the bloodied value they take a -1 to STR and DEX, then perhaps a -2 when they reach 20% of their HP.
So my question is, are there any popular house rules out there that accomplish something like this for Pathfinder? Has anyone come up with something of their own they'd like to share?
I'm not trying to make the game insanely deadly, just spice up combat a bit to make players really feel the significance of damage their characters are taking.