The assumption (because it's all that's been done) is that regen has to be a static amount, rather than scaling with gear or damage taken, or whatever. It could easily scale however you want it to scale though.
It can scale with gear, but it can't with damage. If it does scale with damage then it's not really regen, it's simply armor mitigation given another name.
If you made it to where regen regenerates 25% of each hit then it's almost exactly the same as 25% armor mitigation (the only difference being on killing blows). It's not really regen, it's armor mitigation given another name. We aren't discussing flavor text, we're discussing actual mechanics.
The mechanic we're talking about specifically does not scale with damage. To make it scale with damage you'd have to change the mechanic, and then it's no longer the old mechanic.
Similarly, there's nothing preventing you from creating regen that scales with damage taken. Mob hits you, you lose life, you get a buff that heals you for some % of damage taken over some period of time. Voila, scaling regen.
That's armor mitigation renamed regen. It's no longer the same mechanic as the one we're talking about. If the same thing as if I made doge to where you only "dodge" part of the blow, so maybe you dodge 25% of the blade, but the rest still hits you. You're not cut as deep, but yo're still cut. So you take 25% less damage. That's not dodge anymore. That's armor mtigation renamed and flavored as dodge.
Edited, Jun 28th 2009 7:18pm by Allegory