Someone asked the 411 on Dubas on our board, but i think it got buried with some of the freaking out. (I would also argue if you did get Dubas - you'd probably also inherit Keefe as those two seem to be two peas in a pod).
Dubas was Shanahan's first significant hire in the new regime.. People were excited because of the things he did in the Soo, and because the Leafs were one of the most backwards thinking organizations (ie: not looking at analytics at all), people thought this was Shanahan's way of stepping into the analytics foreground.
Dubas spear-headed the Leafs super analytics compound (basically shutting down a lot of the well-known websites, because he poached all their guys). He also hired Keefe to work for the Marlies, and while I don't know what the GM of the AHL does (some will argue not v. much, some will argue build the minors outside of organizational drafted picks) had an amazing season two years ago (but had a lot of the super rookies), and then had a challenging first half (the Marlies were dead last) but then they made the playoffs, culminating in a 3rd round exit and a 2nd round exit (both game seven losses i think).
Dubas was also our acting GM when Nonis got fired (along with Hunter), and was responsible for the deals made during the 2015 draft., and the UFA signings of that year as well. (though seen as committee based as Babcock did a lot of phone calls too). he did NOT run point on the Kessel trade - that was Shanahan. Some believe that that the Babcock vs. Hunter debate (Marner vs. Defenseman/Hanifin) resulted in Shanahan getting Lou in the first place.
people will feel attached to him because a lot of people thought he'd be instantly named GM when lou stepped down (actually before Lou got here), and Lou said if Dubas wasn't GM here when he goes that's his fault (this was during his introduction speech). However, with Hunter being named something (also Ass. GM?) on top of his head of player development, and this was actually in the papers, how "far" Dubas can go here because Lou said he felt "rejuvenated" and Babcock isn't going anywhere (meaning Keefe can't advance) - this doesn't surprise me this is coming at all.
This also didn't mean Dubas was also the "heir apparent" because Shanahan always seemed like the kind of person who would search EVERYWHERE before deciding. (not just handing it over to Dubas). If he were to be your new GM, you'd probably be seeing a lot of interesting moves - as well as some traditional ones as well, I think.
to be dead honest with you - I don't know if this would be a good thing/bad thing" for you guys. most Leafs fans are freaking out (but they freaked out when Eakins got hired from Edmonton, and some freaked out when Benning/Desjardin got hired in Vancouver). I also cotton to the theory that everyone deserves a chance. (and there's no reason to believe that he can't do a good/great job for you guys) - and I think it will open up some trade lines between Toronto/Colorado which is always good imo.
but you do run the risk of having someone who is an NHL executive virgin for the most part. one thing I didn't like what he did was that he got cute during the 2015 draft and tried to gather many picks as he can (YAY) but at the cost of NOT Drafting Jacob Larsson at 24 (and Anaheim sniped him one spot before we did when Dubas traded down). and that one hurts especially as a lot of people think this kid is gonna be a beast. (but that's just like one thing) - and then Lou took over so who knows. so that's something to keep in mind as well.
i always did like Colorado so i hope whatever happens, y'all can get better real quick.