Not directing this next comment at anyone in particular, but it's almost amusing to see US fans criticize the BBC for it's plans re: DW and how they should take them into consideration. Yet when the shoe is on the other foot and UK fans say they should be taken into consideration for US shows, the line usually trotted out is the UK doesn't matter if it's a NBC/CBS etc.. show.
I'm not sure that the two situations are comparable; the American broadcast networks in recent years aren't producing the kind of pop culture/merchandising phenomena that Doctor Who
is. The American programs that are
the pop culture/merchandise engines are programs on the cable networks with small, cult audiences -- in other words, the same kind of audience Doctor Who
draws in the US.
To the extent that any content producer cares about audiences outside their native territory, it's in the overseas sales they get for selling the show to a foreign network and in the licensing and merchandise sales they get from that territory. If BBC America is still willing to pay for the program (which they are) and if American punters are still willing to buy Doctor Who
merchandise (which they are), then that's all the BBC (specifically Worldwide) should and will care about.