I like the variable modifier rules, but I worry that maybe they won't exactly be conducive to simple game play.
For example, I'm having enough trouble convincing one of my players to total up his attack bonus on the character sheet -- every time he attacks, he rolls 1d20, adds his BAB, adds his Str mod, adds his Weapon Focus bonus, and adds his masterwork bonus. Drives me batty. Trying to get him to convert to and/or track variable modifiers would be an exercise in futility.
Also, this system makes situational modifiers a REAL pain:
DM: "Roll Perception."
Player: "2d20... 13."
DM: "Ok, you hear..."
Player: "Oh, I'm an elf. That's +2; it's a 15."
DM: "No, actually, the +2 makes it 2d20+1d6."
Player: "Huh?"
[Everyone furiously consults tables)
I agree, I'm not exactly a fan of this particular suggestion, having to check a separate table every time I make a roll, you know... like thac0... but for *every* roll...