Holl is simply the fanbase whipping boy. Not that he can't be improved upon... but, he led the Leafs in Hits last year, second in blocks by 2, third on the team in Defensive Point Share, played PK decently well, 23 points, for $2 million bucks. What exactly do you expect for $2 mil?
Sure, he's the target to move, as we'd like Sandin to get into the lineup more, handedness aside.... That's the problem.. RD is a bit of a premium position, and we have two legitimate Right Handed guys, and Holl is one of them. Remove him, and we might be pushing someone to play on their offside, that they aren't particularly suited for... some guys can do it though.
The question on Kerfoot, is does moving him improve the team, and how do you replace what he brings, at a lower cap hit? There aren't many options out there at the moment.