Could this have lasted longer if more American actors were involved?

When it comes to international actors, I do believe Americans prefer to have more Americans involved and speaking English they can understand.
The only 2 things I can remember I am judging this by is 1) Kelsey Grammar recreates 'The Sketch Show' with American actors and keeping Lee Mack from the Original "The sketch show' but doing the same sketches in the original show. My opinion: What the F... for? Would Americans not interested in it because its a UK show? Would American not understand UK accents?

I think same with "men behaving badly" though can't remember much of the American version and British Version but many people say the British one was funnier.

and 2) When Susan Boyle was being interviewed in Scotland for the "Got talent" show and was shown on Oprah, bosses felt the American viewers would not understand her Scottish accent therefore added English subtitles.

There were a few other reasons but I forgot.

I can't remember Season 1 but season 2, there were only 2 American's and the rest were British, Russian, Chechen, French speaking English in their country's accent or speaking in various European languages.
I enjoyed the show, even the jumping between various years to understand the main characters history more, but when heard it was cancelled and only half a million viewers, felt what if this show was more American, would it have succeeded, even for a few more seasons?

E.g. Instead of Sean Bean playing Martin Odum who was originally Russian but was working for MI6, have some American actor who was originally from ..let's say a South American country, but worked for the FBI, would this have worked better for the American audience?