I never got that impression - but I am certainly not an expert on T-Mac in his prime. I never thought T-Mac, even at his best, could create as well as LeBron or Kobe.
Well, the numbers bear out my impression. Look at the Assist Rates. Kobe, in his prime has been between 22% and 29%. McGrady has been between 23-30% (with one remarkable 37.5% season). And it isn't because McGrady has had better teammates to pass to.
I would argue that at his prime his supporting cast was not much different from LeBron's - and LeBron usually lead his team much further in the playoffs.
First of all, James is a significantly better player than McGrady and Kobe. I was comparing McGrady to Kobe, not to LeBron. I think James compares favourably to Jordan...he's beyond players like Kobe and McGrady.
Secondly, those Orlando teams were complete trash outside of McGrady. Players like Zydrunas Ilgauskas, Mo Williams, Anderson Varejao, Carlos Boozer, Delonte West, etc, are no great shakes but far better than players like Andrew DeClerq, an aging Darrell Armstrong, Jacque Vaugn, Pat Garrity, etc. In four seasons in Orlando, he had a teammate surpass 15 PER in a season four times (Darrell Armstrong twice barely, Drew Gooden once and Bo "I'm not Travis" Outlaw once).
I won't get into the imposition of will thing, since that's so subjective and really can't go anywhere but "Yes he did," "No, he didn't." I will note that the narrative is largely driven by the success of a team. Even for Kobe himself. When the team is fighting for a title, the superstar taking it upon himself to "win games" is seen as imposing his will. The superstar doing the exact same thing on a first-round-and-out team is seen as a ballhog. As I said, this switch in narrative sometimes happens to the exact same player. When the Lakers flailed out of the playoffs against the Suns some years back, I read tons of stuff about how Kobe was selfish. In fact, the same was said when the 2004 Lakers were upset in the Finals. Kobe didn't change his game, he just got an upgrade in teammates. Now he's imposing his will to lead his teams to titles.
McGrady has been alternately accused of being selfish (when he's tried to take games over because his teammates weren't getting anything done) or passive (when he spent periods of games getting his teammates involved). The moral of the story, IMO, is that, in terms of perception, you cannot possess a virtue when you're on a losing team, and everything's a virtue when you're on a good team.