I think Ebisu isn't a very good example because it doesn't work well for racing with a full size grid as there's not alot of safe overtaking points and there's a limit on the type of car you can take on it, if they're going to make a specialised drift track that is suitable for only a few cars, I'd rather have a Fujimi Kaido rip off (I don't care if they're stealing it from Forza, make it in Europe and nobody will know

). A Fujimi rip off would also be like a tarmac rally stage, win-win you cater to 2 niches at once, sure course editor tries to give us a taste of this but it's so limited and bland.
Rallycross wasn't a great example, the main point I'm driving at it is they can cater well for the main crowd with a large circuit capable of accommodating a large range of cars but which also has an appeal to another audience. Silverstone seems perfect for this, given we only get 1 track every so often it needs to be something special an Ebisu would be as disappointing for serious racing fans (imagine LMPs or a full GT1 grid on Ebisu

) as Route X was for many of us.
In other words I'd rather them give us another world class circuit which is also used for drifting, or go the whole way and make something completely unique to the series.