I think the point one poster made about how bad the Leafs were before Gilmour is very important.
It is part of why he is seen as such a Leaf icon.
The hero saves a damsel in distress, not one who is doing ok on her own. The Leafs were definitely a damsel in distress. Whether Gilmour single handedly saved them might be up for debate, but the team absolutely did turn around upon his arrival.
Sundin through no fault of his own, was not part of a team that turned an embarrassing franchise around.
It is interesting that it seems to be the younger folks in the Sundin camp and the older ones in the Gilmour camp. Let us remember the older ones were around for both.
Myself, I remember from Keon as captain. I would list Gilmour and Keon as my all time favorite Leafs (who aren't goalies)
I liked Sundin, though I was underwhelmed at first and bitter at the dealing of Wendel, but I grew to really like and appreciate Sundin. However he simply never captured my imagination the way Keon or Gilmour did. It isn't about stats or nationality either. And it certainly isn't about Don Cherry's crush. I just love the way Keon and Gilmour played, and the leadership they brought. Even before Dougie was captain he was a team leader.
As for how they ended there time as Leafs, I don't remember if Dougie asked or not. I do remember it was rumoured he would be traded for quite a long time before it happened, and many felt he had to be traded for the team to build going forward. I was very dissapointed when it was announced.
Sundin for me was worse. He claimed he didn't want to be a rental, and thus didn't let the Leafs deal him to get something in return. Then he signed essentially as a rental for the Canucks.
I absolutely would have preferred it if he had allowed the Leafs to trade him to build for the future.
All of that said, I'd LOVE to have either of them in their primes on the Leafs today.