This favors Dirk significantly. Here are the rankings from BBR which is O rating and D rating adjusted for HCA and opponents
http://www.basketball-reference.com/blog/?p=9217
Post-deadline, The Thunder were the #3 in the league, Lakers #4, and Blazers #9.
Blazers: The Blazers were a 5.35 SRS team with Gerald Wallace. They improved to 7.76 SRS in the 14 games he started (beat the Spurs x2, Mavs x2, Lakers, Grizzlies, and Thunder). They also significantly out talented the Mavs. Here is the comparison between the two teams minus their best player:
Blazers: Wallace, Miller, Camby, Matthews, Roy, Batum, and Fernandez. That is a significant talent gap. Gerald Wallace would be the best player on the Mavs. Everyone one of those guys is solid.
Lakers: In the 2nd half of the year+1st round, the Lakers had a 7.71 SRS in the games Bynum played.
Lakers: Gasol, Bynum, Odom, MWP, Fisher, Barnes, Blake, Brown
Another significant talent gap. Gasol, Bynum and Odom would have been the best players on the Mavs (ignoring Odom's horrific Mavs stint). This talent gap is around the same level as the 04 Lakers vs. 04 Wolves except the Mavs swept the Lakers without HCA while the TWolves lost with HCA in 6 games. I don't think the talent was big enough to overcome the 6 game gap in outcome.
Thunder: 7.22 SRS in the games Perkins played+first 2 rounds. Look at the linkI posted up earlier. The Thunder were a top 3-5 team post deadline. This is another team with a big gap in talent:
Thunder: Westbrook, Harden, Ibaka, Perkins, Collison, Thabo, Maynor
Westbrook is easily much better than any of the players Dirk played with. Harden would be right up there with Dirk's 2nd best player. Harden averaged 15-6-4, 126 O rating, .634 TS%, per 36 minutes in the playoffs. Terry was 19-4-2, 119 O rating, .604 TS% in the playoffs so both of those guys were not far off. And Terry was Dirk's 2nd best player in the playoffs. It's a very close comparison if you take into account what Terry was doing with Dirk off the court (.551 TS%). Ibaka, Perkins, and Collison are better than the non-Chandler/Marion/Terry players. This Thunder team was better than the 04 Kings.
Heat: This is self-explanatory. One of the biggest upsets in finals history based on talent. The Heat entered the finals with a 27-6 record and 9.25 SRS in their past 33 games as they got healthy (Miller and Haslem being healthy). Overall for the whole season, the Heat had a 7.82 SRS in the games that the Big 3 played. The Big 3 over the past 2 years were a +14.4 team when they were on the court together and in the finals they played about 40 MPG. The Heat got rid of some of their bad players and played Chalmers, Miller, Haslem, and Anthony more. This was an elite team that beat just came off of beating the Bulls without HCA in 5 games. The Bulls with their starters healthy were a +8.14 SRS team and the Heat easily beat them.
Heat: Wade, Bosh, Chalmers, Haslem, Miller, Anthony, Bibby
The only real horrible player there is Bibby but his minutes were reduced in the finals. Wade was another level compared to Dirk's players. Wade was an MVP caliber player. Bosh was an all-star who was also better than Dirk's cast. Chalmers, Haslem, and Miller would have fit well with Dirk's role players. If KG lost this series, his fans would make so many excuses saying he couldn't be expected to beat LeBron/Wade and Bosh at the same time (see how a loss to a weaker Shaq/Kobe duo was excused). Dirk did it himself (had a Plus/minus of +40 in the finals). And Dirk also did it without HCA advantage on his side. You can't tell me the gap in talent between 04 Wolves and Lakers is that much bigger than the gap between 11 Mavs and Heat to explain the huge difference in outcomes.
Dirk beat 6 out of the 9 non-Dirk players in the All-NBA first and 2nd teams. And Dirk beat 3 teams that each had 2 1st/2nd team All-NBA players. The Heat also added an All-star in Bosh who wasn't an All-NBA player. Aldridge also made 3rd team all-NBA and Dirk outplayed him H2H. So that's 7 All-NBA players and 8 All-stars (would have been 9 if Bynum was healthy all year). Yet Dirk did this with no all-stars on his side. Dirk hasn't had an All-star player by his side since 2007 and hasn't had an All-NBA player since 2003 yet he had plenty of success in that span.