Yeah... without the ROF/PEN/DMG distinction, it would seem things would be much less fun. Also, that distinction would make the number-crunching very difficult for a one-roll system.

Just musing out lound, I guess...

You'd have to have a larger die to roll, and adds/negatives like the Old D&D system had (ain't played the new D20 sytem - likely won't ever).

While I like the concept of a single roll, I can't see how you could easily make it work.

Now, if you rolled a fistful of dice at one go, that could be made workable. While you'd drop the ROF idea, you could vary the weapons by the die type you use to address penetration, and each die in excess of the target's 'protective' value would be a hit - rather like Iron Stars, actually.

ROF would actually be addressed in the initial fistful of dice as extra dice I suppose...