Yeah, it's an interesting question. I dunno. I'm not sure it's even relevant to consider what the respective teams did after, is it? I mean, the point is how good they were during their runs, not how good/bad they were months/years later. Not the point.
Honestly, all three were not expected to go on playoff runs. The Canucks couldn't get past Edmonton in '92, and were Gretzky-ed by Los Angeles in '93 in a year when they really should have beaten the Kings. In 1993-94, they took a big tumble downwards in the standings, and I remember thinking they probably were done as a contender. But after one of those 1-3 series comebacks (as often seems to happen), they gelled and went on a great run.
Even as an Oilers' fan, I was glad to see Calgary back in the playoffs in '04, and I cheered for them. Iginla was just awesome, and Kiprusoff also. They probably just didn't have quite enough depth at forward to get the job done (although, had their been 'electronic tracking' of the puck, they might indeed have won the Cup in game six of the Finals, in overtime...but never mind).
Edmonton clearly became a much better team around the mid-point of the 2005-06 season, and then consolidated it with the trade-deadline acquisitions. In their first 19 games, they were only playing at .500 level, but after that went 32-19-12, which isn't too shabby. (The '04 Flames likewise were only .500 in their first 18 games.)
I'm tempted to say Vancouver was the least surprising and therefore was the best team... They certainly had the most depth at forward. But then I think of how they were 1-shot away (three times) from being eliminated in round one, and also of how Calgary and Edmonton faced (I think) stronger competition on the way to the Finals...
What I would suggest is that Calgary '04 and Edmonton '06 were teams "built for the playoffs", as the saying goes. Edmonton had the best D-man (Pronger) of the three teams, and Calgary maybe had the best goalie (Kiprusoff). Those two teams were designed to take down more talented, deeper line-ups (and did). The '94 Canucks were more like a really strong group of players that had failed to gel consistently during the season, but then went on a run starting halfway through round one. The Canucks obviously had the game-breaker (Bure) that the others lacked, though Iginla was no slouch in '04.
In conclusion, I dunno. At the end of the day, each team achieved exactly the same thing (game 7 Finals' loss), so I guess they were even.