I completely agree with that analysis of Mackinnon. I'm a huge Avalanche fan so I will do what I can to get him, but when I get him the plan is to keep him forever, and it's not worth it in that sense until he drops down to mid-pick range.
As for Perry, that is a really interesting stat to note. My league is 3RW though, and I'm not quite sure that I'll be able to redraft 4 capable RW players so I don't know how much this would come into effect.