Reaves is 6'1 and around 225 lbs. Typically, when people use the term "pound for pound" it's in reference to a smaller than average guy who can still go with the best of them.
Ex 1. Bob Probert was the better overall enforcer, but Tie Domi likely would be the first choice as "pound for pound best fighter" during his team.
Ex 2. Deryk Boogaard was the better overall enforcer, but Rick Rypien was arguably the best "pound for pound" fighter.
So I don't think Reaves fits the description because he's neither short nor underweight (for a fighter).
I disagree with how pound for pound is looked at by most. Just because a guy is on the smaller size doesn't mean he's instantly in the P4P discussion. I like to look at guys and imagine they're all the same size, everyone, say 6'0'', 200 pounds. Who's style is the best? Who has the most power? Who's got the best stamina, etc.
Also, I liked Rypien, but he's not pound for pound the best anywhere. The guy was great against guys his size, and against god awful bigger guys, but had trouble with guys like Neil, Carkner etc. A guy like PJ Stock fits the bill if you're looking at size. He was undersized and fought pretty much all the big time enforcers much heavier than he was, and did very, very well.
Right now, the best two fighters in the NHL are Ryan Reaves and Milan Lucic, I'd say. Regardless, they're the two best pound for pound dudes. Guy's like Simmonds are good too, but rarely fight outside their league, lets say. Same goes for Bieksa. A guy like Michael Haley is in that class as well, however Haley often times fights outside of his height/weight.
Height and weight mean nothing to me when i'm looking into pound for pound.