Funny you mention that, Im currently reading Subtelny's book.
I really cannot comment too much on the Rusyn question. Like you, Im moderate but slightly biased towards the position they are Ukrainian. However I do not believe that the Ukrainian identity can nor should be imposed on them, just like it was wrong for the Russian identity to be imposed on us.
If they are a seperate nation, then lets enter peaceful and cooperative relations with them.
The British question is a little complicated, although Andrew Wilson offered some comparison to the Ukrainian/Russian question.