My reasoning for picking Shanahan here is that while those Red Wings teams were a murderer's row of future HOFers, Detroit had an extensive history of playoff disappointment by this time. Detroit had at least a couple of seasons before 1997 that featured a lot of those same players, and a couple more great players who ultimately didn't stick around for the championship.
1994:
Yzerman
Federov
Lidstrom
Coffey
Kozlov
Konstantinov
Primeau
| 1995:
Yzerman,
Federov
Coffey
Lidstrom
Fetisov
Konstantinov
Kozlov
Primeau
Vernon
Osgood
| 1996:
Yzerman
Federov
Larionov
Fetisov
Lidstrom
Konstantinov
Coffey
Kozlov
Primeau
Osgood
Vernon
|
Those were teams that were loaded with talent but couldn't get over the final hump until Shanahan arrived (in exchange for Primeau and Coffey, and later Murphy was brought in to replace Coffey on the back-end in a coup of a deal for Detroit with Toronto).
Conversely, Chicago was just starting to come into their own as a premier franchise, fresh off a Conference Finals appearance when Hossa signed there. Kane and Toews were only in their third seasons and were nowhere close to developing the choker label that hounded Yzerman and the Wings for years before they finally won. Granted, Chicago didn't have as many future Hall of Famers on their team but this was in the cap era, teams couldn't just load up on established veteran star players by spending maximum money. If they could've I'm sure many more players would've signed with Chicago like they did with Detroit, Colorado, Dallas, and New Jersey back then. This also meant that while there were a ton of have-not teams in the league, those at the top were absolutely loaded with star players and the competition was fierce. Without the cap Chicago may have also been able to keep that 2010 team around a while longer.
Hossa had strong seasons and playoffs for Chicago's championship years, but I would say Shanahan was more critical during the Wings' winning years than Hossa was to the Blackhawks.
Shanahan:
1997: 1st in Regular Season Scoring, 2nd in Playoff Scoring
1998: 3rd in Regular Season Scoring, 10th in Playoff Scoring
2002: 1st in Regular Season Scoring, T2nd in Playoff Scoring
Hossa:
2010: 5th in Regular Season Scoring, 7th in Playoff Scoring
2013: 3rd in Regular Season Scoring, 4th in Playoff Scoring
2015: 3rd in Regular Season Scoring, 4th in Playoff Scoring
Now Hossa was injured to begin 2009-10 so adjusted for a healthy 82 games he'd have been 2nd in regular season scoring that year. And in 1997-98 Federov had a long holdout so who knows how the scoring would've looked had he and Detroit came to an agreement earlier. And in 2001-02 Yzerman missed a good chunk of time with an injury and adjusted he paced for 75 points over a full year which would've tied him with Shanahan (who missed a couple of games himself so he might still have come out ahead by a couple of points). Regardless, I find Shanahan's leading point totals on teams that oozed talent to be more impressive than Hossa's high production that still had him come out behind Kane and Toews. It's also jarring to see Hossa still end up 3rd in scoring in 2015 when Kane missed 21 more games than Hossa but still outscored him.