Milan Michalek is on pace for his best NHL season, scoring 40 goals and 58 points (I love TSN.ca's on-pace stat), but Jonathan Cheechoo have proven all of his doubters correct with only 2 points so far this season. Some nights, he barely sees the ice, and other nights, it seems like he can barely skate.
Kovalev has, so far, lived up to his billing as a streaky scorer. Undoubtedly, he has crazy moves--but little results to show for them. Despite some fancy playmaking with Jason Spezza, Kovalev has not, in my view, lived up to my optimistic expectations.
But the real question is: Are these elements adding up to wins?
It's difficult to make the argument that the Senators would be better off without Michalek and Kovalev, but it's the Senators' old guard that has been the major contributors to the Sens moderate success so far this season.

The Sens just need a couple more players to have above-average seasons in order to ensure themselves a playoff spot. That means Nick Foligno contributing more offence on the third line, and Cheechoo at least hitting 15 goals this year.
It's no secret that it takes a whole-team effort to make the playoffs in the NHL, and if even two lines contribute the offence, the third still has to make its contribution.
PS: I saw my first instance of someone calling Pascal Leclaire 'inconsistent' today. Does that make him a good goalie that sometimes plays poorly, or a bad goalie that make the occasional incredible save? I hope it's the former.