I disagree for several reasons.
1) The Cuylle-Chytil-Kakko line is fine. They will score in the playoffs, the same way the Laf-Chytil-Kakko line did 2 years ago. Maybe better. If you don't want Cuylle or Kakko scoring in the playoffs, then sure, moving them to the 4th line would do that.
2) There's a good chance Perreault will join the team at some point, so he can be that guy if we need him. If not, we have Othmann and Berard in case there are injuries.
3) Who are you getting to play RW and how much will that player cost? In the past 2 years, look at the players we have brought in at the deadline to play RW. Have any of them really made a difference? Smith was our move to fix the RW spot and is fitting in. Laf is Laf, and the third line is producing.
4) We have limited assets. I'm not interested in wasting a 1st round pick on a rental just so that player can cannibalize another player's production. We're the highest scoring team in the league. If our offense falls off a cliff, then we can address it.