Since my return to BRP and it's total conquest of all other game systems at our table, roughly 2 years ago, we have been pollishing and honing our house rules to get to the point where we are at now where we are using BRP (with our house tweaks) for settings as disparate as Middle Earth, Battletech/MechWarrior, 40K, and a gritty realistic Twilight2020/Terminator setting.
We now feel confident for the next step, which has been mooted for at least a year, smoothing out the seeming inconsistency of having 3D6 attributes in a D% system, and removing the rather artificial concept of hps. Both of which seem to be holdovers from D&D, that actually don't do much for the system.
So, as a test run, I am presently preparing a new campaign set in my old D&D homebrew world, for a thief character, where we are using percentile attributes (starting as 40+5D10), and without the concept of hps. I shall post some rules under here so you can see how combat will work. We use the Harnmaster hit location tables, which give specific locations hit down to each finger, and a more generic Light Wound, Medium Wound, Severe Wound, Kill, damage mechanic.
By rationalising the old 3D6 attributes to percentile it brings them much easier into line with skills, where Difficulty Code tests can be made against both skills and attributes (a DC10 test from a module would be a no adjustment test, DC11 would be harder - a minus 5% test, DC12 minus 10% and so on).
Big or particularly nasty/tough monsters, rather than dozens of hps will have Damage Reduction.
I've a feeling this will work smoothly, especially once we're used to it. Has anyone else tried something similar?