Yeah, why wouldnt you want a 2nd Dan Marino, John Elway, Joe Montana, Peyton Manning or Daunte Culpepper if you could find one?
The reason most teams have a different unique skilled backup QB is because its hard to find an exact replica for a reason. But that shouldnt make you avoid a natural as close to the same QB from being on your team if one exists.
OC's would love it, Lineman would love it, etc. The bottomline is winning. Would you want 2 Joey Harringtons? doubt it. Would you want 2 Joe Montana's or Terry Bradshaws? Absolutely if you could find them.
Now I am not saying you praise Russell for being a DC clone, but you dont avoid him like the plague if you believe DC is the right QB for this team. Thats the coaches call, and if they decide to select Russell it would make a lot of sense.