It's not a matter of spin, at some point there's just the fundamental reality that a team can only really have 6 forwards that they give significant PP time to(or, at least, if you start giving PP time to forwards 7-9 you're taking it away from guys 1-6). So the extent to which it's Raymond and not Clarkson who "replaced" MacArthur is 100% true in the sense that Raymond is filling the role for the Leafs that Mac is with the Sens. If Grabo, Mac and Raymond were all on the team together, then two of those guys would be getting very little PP time and playing on the 3rd line.
Someone saying that they'd rather have a Mac-Grabo-Kulemin third line than a Kulemin-Bolland-Clarkson one is presenting a legitimate argument. Doing so on the basis of offensive totals those guys are putting up in offensive roles, however, is nonsense. It's like pretending that Mike Ribeiro replaced Boyd Gordon in Phoenix.