He's unanimously considered the best coach in the league, he gets to dictate the terms of his contract.
Coaches are so hard to rate. Look at the Jack Adams winners since the lockout.
2005-06: Lindy Ruff (Sabres) - fired
2006-07: Alain Vigneault (Canucks) - fired
2007-08: Bruce Boudreay (Caps) - fired
2008-09: Claude Julien (Bruins) - in jeopardy
2009-10: Dave Tippet (Coyotes) - has been in jeopardy for a while
2010-11: Dan Bylsma (Pens) - fired
2011-12: Ken Hitchcock (Blues) - most likely going to be fired
2012-13: Paul Maclean (Sens) - fired
The only coach that is pretty safe since the lockout is Roy, and he was just hired last season. Look at when Ruff got fired, when the Sabres got bad. Vigneault, after the Canucks choked multiple years in a row, and needed a scapegoat. Boudreau, Bylsma, probably Hitchcock: same as Vigneault. MacLean when the Sens got bad, maybe Claude since we're getting bad. Babcock has never won a Jack Adams trophy, but his job has never been in jeopardy. He's undoubtedly the most consistently good coach in the league. IMO, that's what you look for in a coach. Sure, Ruff/Vigneault/Boudreau left their teams and joined others and have had a lot of success. But they got fired because their teams got bad. Detroit has never been bad... They've never needed an excuse. Babcock is leaving on good terms, he wasn't fired. He's not going to have the luxury of having a guaranteed good team in Toronto.
Babcock vs. other coaches is almost like Kessel vs. Bergeron. Do you want one guy who's going to be elite some nights, but invisible for most of them, or someone who is going to be consistently good in multiple areas, and a proven leader? Most teams will take the Bergeron, Babcock. He's the best coach in the league, sure, he's earned that title. But I have a feeling that's going to change in the mess that is Toronto.