Some of these have been touched upon in this thread, but here's my take:
-Their play in Babcock's systems just seemed to work like a well oiled machine
-Their best players were at the beginning of their peak (Datsyuk and Zetterberg) or well within it (Rafalski and Lidstrom).
-A lot of their young guys made big strides over the year before (Hudler, Filppula and especially Franzen and Kronwall)
-They had a HUGE "window" open with so many guys on contracts with AAV's much less than what they were contributing (IE Zetterberg on a bridge deal with a cap hit of $2.65M, guys like Kronwall, Cleary, Samuelsson, Filppula, Hudler, Franzen, Osgood all making near or well under $1M)
-Franzen got absolutely white hot to end the year (12G, 6A in 56 games from the start of the season until the end of February. 15G, 5A in 16 games for March and April.
-The swapping of Schneider for Rafalski and the addition of Stuart gave them arguably the best top 4 on D (Lidstrom, Rafalski, Kronwall, Stuart) they've had since 96-97. Stuart complimented him so well that Kronwall ended up really turning it on during the playoffs.
-They were a really deep team. Aside from Datsyuk and Zetterberg, they had 8 other forwards that could've arguably been top 6 guys on a lot of other teams at that time. They were also solid down the middle with Datsyuk, Zetterberg, Filppula and Draper at C. Some injuries allowed them to bring up Darren Helm at the end of the season and he ends up becoming a regular on the 4th line in the playoffs. Once Stuart was brought in, they had a rotation of Lilja, Chelios and Lebda for the 3rd pair, and Meech, Quincey and Ericsson ready to step in if needed.
-The additions of Drake, Downey and a healthy (for the regular season) Kopecky, and then eventually McCarty, Stuart and Helm made a team that had a reputation of being super soft the past couple seasons, a much tougher and more physical team. I think I lost count of how many times Dallas Drake gave up any regard for his 39YO body to absolutely destroy Stephane Robidas and a few other players in that WCF against Dallas.
-Chris Osgood, who had kind of been written off as an oft-injured back up goalie going into that season, found a fountain a youth that offseason. He played great during the regular season and mostly stayed healthy playing a #1B to Hasek and then was even better when he took over for Hasek in the playoffs.
I also do think that the distaste from the 2007 Western finals motivated the team, though honestly seeing Anaheim, which was always a bad matchup for Detroit in that time frame, significantly weakened was a big help.
I disagree that the Ducks were a "bad matchup" for the Wings at that time. It took the Ducks 6 games in 2007 to eliminate a Wings team that had no Schneider or Kronwall, with 45YO Chelios playing as #2D, Lilja and Lebda playing 20 minutes a game and 21YO Kyle Quincey dressing just to take a small handful of sheltered shifts every game. They then took the Wings to 7 games in 2009, but the Wings had no Lilja, Rafalski was out for games 1-5, with a rookie Jonathan Ericsson in the top 4 and a near crypt-keeper level Chelios dressing for all but 1 game. They also didn't have one of their best FO and PK guys in Kris Draper for all but 1 game.
I'd have my money on a healthy 2008 Red Wings stomping the 2007 or 2008 Ducks. They would've needed Pronger and Niedermayer to team up to slam some more heads into the glass in hopes of taking guys out, or get Brad May to sucker punch Lidstrom like he did to Johnsson to get past them.