I am having a very difficult time understanding why immediate and ongoing reactions to this trade are so frequently negative. Nonis made it pretty clear that his depth position is a wash for Liles', so it's not like he's being expected to become the second coming of so-and-so from the early nineties or aughts. As has been stated, we can also count on the relative financial wash between the contracts of Liles and Gleason, so frustration there makes little to no sense at all.
Those two equalities, when considered with the idea of upgrading in the size of the #7 defenseman and, hopefully, the continued emergence of Rielly and Gardiner, make Liles much more burdensome moving forward, even if slightly cheaper than Gleason.
Ideally, he would be expected to work himself into the lineup at Fraser/Ranger's expense, which is nothing to get excited about. Criticisms of his career failings in Carolina are more than fair, as are injury concerns. But at the price, it's worth a gamble to have an experienced, defense-first defenseman around, especially if he can eat up some of Dion's defensive workload (I am by no means a full supporter of Phaneuf, but statistically, there is almost nothing anyone can offer him in terms of criticism), which in the current lineup is pretty much nonexistent.
About the worst possible outcome for this trade is that we will have the style of player we lack most (apart from potentially a top-line forward) sitting in the stands, rather than a redundant offensive defenseman.
I suppose a secret worst-possible option would be if the Colorado trade rumours are true, and Gardiner ends up part of a top-line deal. Rielly has shown some very poor decision making this season, and i would hate to see him bear the full brunt of the madness at the center of the universe, simply because we traded away our other blue-chip defensive prospect.
Whatever happens, i hope Gleason finds a nice vein of form and fitness while in Toronto, and that Liles doesn't, as one of our more pedantic, cynical members suggested, become the missing piece of the Carolina puzzle, if such a yard sale of questionable decisions can be solved, or at all hacked back together. Not to be overly critical of the guy, since it is kind of his thing, but suggesting that a team more offensively anemic than we are, with comparably difficult defensive problems to work out, as well as the very real possibility of Cam Ward being past it, just needs a little help on the powerplay to make up the (as of this morning) 5-point gap on the wild card spot is pretty unfair to both Carolina and Toronto's realities--not to mention the Senators, Devils, and Rangers.