After seeing Bill Madden's article in the NY Daily News I decided to list all the DH's and NL DH's from the World Series since 1976 (1994 will be a what could have been, all hypothetical like) to see what the difference in production has been.
All the box score information was taken from Retrosheet.
1976
CIN: Dan Driessen: .247/.362/.407; .296 EqA
NYY: Carlos May: .278/.358/.361; .278 EqA
Driessen outhit May in the series as well, going 3/6 with 2 BB and 3 runs scored.
1978
LOS: Lee Lacy: .261/.335/.518; .297 EqA
LOS: Rick Monday: .254/.348/.468; .291 EqA
NYY: Reggie Jackson: .274/.356/.477; .293 EqA
Well that is intriguing huh? On paper they were basically equal, but as far as the series went the Yanks and Jackson took the win here.
1980
PHI: Keith Moreland: .314/.341/.440; .278 EqA
PHI: Lonnie Smith: .339/.397/.443; .299 EqA
KC: Hal McRae: .297/.342/.483; .284 EqA
1982
STL: Dane Iorg: .294/.352/.361; .266 EqA
STL: Lonnie Smith: .307/.381/.434; .297 EqA
MIL: Don Money: .284/.360/.531; .305 EqA
1984
SD: Kurt Bevacqua: .200/.326/.275; .241 EqA
DET: Barbaro Garbey: .287/.325/.391; .255 EqA
DET: Johnny Grubb: .267/.395/.432; .301 EqA
1986
NYM: Danny Heep: .282/.379/.421; .290 EqA
NYM: Kevin Mitchell: .277/.344/.466; .289 EqA
BOS: Don Baylor: .238/.344/.439; .269 EqA
1987
STL: Tom Pagnozzi: .188/.250/.333; .211 EqA
STL: Terry Pendleton: .286/.360/.412; .273 EqA
STL: Tony Pena: .214/.281/.307; .215 EqA
MIN: Don Baylor: .245/.360/.392; .249 EqA (with Minnesota; .265 with BOS)
MIN: Randy Bush: .253/.349/.413; .264 EqA
1988
LOS: Mike Davis: .196/.260/.270; .217 EqA
LOS: Danny Heep: .242/.341/.255; .250 EqA
OAK: Dave Parker: .257/.314/.406; .262 EqA
OAK: Terry Steinback: .265/.334/.402; .274 EqA
1989
SF: Ernie Riles: .278/.339/.404; .277 EqA
OAK: Dave Parker: .264/.308/.432; .268 EqA
1990
CIN: Hal Morris: .340/.381/.498; .304 EqA
OAK: Harold Baines: .284/.378/.441; .293 EqA OAK (.294 in TEX)
1991
ATL: Lonnie Smith: .275/.377/.394; .283 EqA
MIN: Chili Davis: .277/.385/.507; .300 EqA
1992
ATL: Lonnie Smith: .247/.324/.437; .280 EqA
TOR: Dave Winfield: .290/.377/.491; .299 EqA
1993
PHI: Ricky Jordan: .289/.324/.421; .263 EqA
PHI: Mariano Duncan: .282/.304/.417; .251 EqA
TOR: Paul Molitor: .332/.402/.509; .311 EqA
1994
MON: Rondell White: .278/.358/.464; .276 EqA
NYY: Jim Leyritz: .265/.365/.518; .291 EqA
1995
This is an interesting case, as the Braves chose to start their regular LF Ryan Klesko as the DH while allowing Luis Polonia to take over in LF. I will use Klesko as the DH though, since Polonia was supposedly out there to shore up the defense.
ATL: Ryan Klesko: .310/.396/.608; .321 EqA
CLE: Eddie Murray: .323/.375/.516; .294 EqA
1996
ATL: Ryan Klesko: .282/.364/.530; .295 EqA
ATL: Terry Pendleton: .238/.290/.345; .202 ATL (.232 FLA)
NYY: Cecil Fielder: .252/.350/.484; .270 EqA NYY (.271 DET)
1997
FLA: Jim Eisenreich: .280/.345/.372; .259 EqA
FLA: Darren Daulton: .262/.371/.429; .285 EqA
CLE: David Justice: .329/.418/.596; .324 EqA
1998
SD: Jim Leyritz: .276/.384/.467; .293 EqA SD (.297 BOS)
SD: Greg Vaughn: .272/.363/.597; .320 EqA
NYY: Chili Davis: .291/.373/.447; .277 EqA
1999
ATL: Jose Hernandez: .266/.339/.425; .231 EqA ATL (.271 CHI)
ATL: Keith Lockhart: .261/.337/.311; .232 EqA
NYY: Chili Davis: .269/.366/.445; .273 EqA
2000
NYM: Mike Piazza: .324/.398/.614; .327 EqA
NYM: Lenny Harris: .260/.317/.381; .292 EqA NYM (.166 ARZ)
NYY: Chuck Knoblauch: .282/.366/.385; .256 EqA
2001
ARZ: Erubiel Durazo: .265/.373/.444; .275 EqA
NYY: Chuck Knoblauch: .250/.339/.351; .252 EqA
NYY: David Justice: .241/.333/.430; .260 EqA
2002
SF: Tsuyoshi Shinjo: .238/.294/.370; .241 EqA
SF: Shawon Dunston: .231/.250/.286; .190 EqA
SF: Pedro Feliz: .253/.281/.336; .220 EqA
ANA: Brad Fullmer: .289/.357/.531; .295 EqA
2003
FLA: Jeff Conine: .282/.338/.459; .277 EqA (BAL and FLA)
NYY: Jason Giambi: .250/.412/.527; .317 EqA
2004
STL: Reggie Sanders: .260/.315/.482; .267 EqA
STL: Marlon Anderson: .237/.269/.379; .224 EqA
BOS: David Ortiz: .301/.380/.603; .309 EqA
It seems as if a powerhouse DH in the World Series is a rare occurrence. In many cases the NL team actually boasts the better hitters, which would negate the AL's supposed advantage. In some cases better hitters were left on the bench, such as in 2004 when John Mabry twiddled his thumbs while Marlon Anderson batted out of the 9 spot as a DH. I feel that if an organization cannot come up with one guy capable of coming off the bench and hitting as a DH in the World Series than they have issues more serious than whether or not the DH is good for the game to deal with. There is always a Triple-A slugger or a free agent or a trade to be made that could boost your bench before the playoffs and provide an NL squad with a DH for 3 or 4 games. The fact that the AL has to drop the DH in favor of a pitcher is more of a disadvantage than the fact that the NL has to come up with a DH. I understand alot of fuss is made over the game not being "pure" and other things such as that, but the NL is capable of coming up with a capable hitter for 3-4 games. It is all there in front of you right now to see.