The Ovi-Backstrom-Kuz Bermuda triangle is an old problem.
All of these players, especially Ovi, have problems with work-rate. Ovi doesn't have the stamina, Backstrom is missing a top gear, Kuz can fly but relies more on skating proficiency and does not have a great motor for stop-and-start hockey (which sometimes is necessary).
For a long time, my opinion has been that each of these guys ideally needs two linemates with great motor, especially for today's NHL. This is why they struggle (or don't impress) when playing together. The other team can outwork them by a big enough margin to negate any talent disparity.
It makes sense to try them on different lines, Ovi with Eller, etc. But I think it's pretty clear that Trotz will never try Ovi out of the top-6 (until his scoring drops precipitously), so we'll continue to see Ovi-Kuz and Ovi-Backstrom problems. In Trotz's defense, I think most coaches would not dare either. It breaks their programming.
On a slight tangent, purely as a Gedankenexperiment (hehe), would be interesting to see Backstrom & Kuz on the same line at ES. Can't afford to do that... but would be interesting to see what chemistry they might develop -- and whether it could be enough to overcome motor deficiencies, esp. with Kuz freed from center duties. With Vrana as the 3rd guy, for example.