If you're using 4 years running as your criteria, you're omitting alot of forwards..including Anisimov, Atkinson, and Brassard (only played 30 games in 08-09), and others who haven't seen consistent top 6 minutes (Dubinsky, Foligno).
Scoring by committee will likely be the M.O. for this team. I won't argue that RJ isn't a consistent B level scorer, but I wouldn't call him our best scorer.
If you prefer, I can rephrase it as "the only member of the team who's scored 25 goals or more in the NHL, ever." (He's done that or better twice - his best is 26, for the record - his first year here. He has never gone below 20 as a Blue Jacket. Dubinsky has one season - in which he DID get regular top-6 minutes - where he managed 24, and another in which he managed 20. Everyone else is in the 15-19 range.)
Facts is facts, and right now them's the facts. Whether or not that changes in the future remains to be seen. He is our best proven goal scorer. Deny it all you like. Rationalize it all you like. Try to sidestep it all you like. The facts are unchanged. The sudden irrational hatred for him (after his three-time "fan MVP" treatment) is inconsequential. He's still our best proven goal scorer. He will be on the top line. (Probably with Atkinson, who is our best likely future goal scorer.)
I have nothing against any of the other forwards here. They may outperform Umberger this year, and that would be perfectly fine. They're vital. They will score. I will love it every single time that they do. But there is absolutely zero - ZERO - justification for not having Umberger on our top line right now outside of sheer bloodyminded irrational prejudiced "but he's supposed to be a THIRD LINER!" whining.
Get over your prejudices. We're scoring by committee and right now he's the best committeeperson we have. That is an indisputable, irrefutable fact.