I totally agree, and to put up that margin of dominance over the next closest pitcher is a good way to compare pitchers from different eras. The fact that he dominated so much during a "hitting era" makes his numbers more than astounding. Add to that, the fact that he pitched in a hitter's park.
His 7 year period is also probably the best 7 year stretch (1997-2003) in MLB history, when you compare his numbers to the league norm or his closest competitors.
His 5 year stretch from 1999-2003 might not even be debatable. To me, it was clearly the best of all time.
1999 to 2003
American League
Pedro Martinez
ERA: 5.03, 5.09, 4.67, 4.57 & 4.66
P.M.: 2.07, 1.74, 2.39, 2.26 & 2.22
WHIP: 1.49, 1.49, 1.40, 1.37 & 1.38
P. M. : 0.93, 0.74, 0.93, 1.10, 0.92, 1.04
K/BB: 1.68, 1.65, 1.59, 1.58 & 1.54
P.M.: 8.50, 8.88, 6.53, 5.98, & 4.38
Pedro only pitched 116 IP in 2001, but he had the top 4 fWARs from 1999-2003:
11.6 in 1999
9.4 in 2000
7.4 in 2003 & 2004.
His 2001 fWAR of 5.5 in just 116 IP placed 17th!
Halladay had 3 seasons in the top 8. Mussina had 4 seasons in the top 12. Those were the closest.
All 5 of Pedro's seasons in the period saw him lead the AL in FIP.
I'll leave it to others to prove I'm wrong about this being the most dominating 5 year period in MLB history.