I have finally begun watching these (and caught up on season one). I didn’t like the idea of anyone “updating” Sherlock Holmes (and couldn’t see how anyone could compete with Jeremy Brett’s portrayal), but these shows are very good. Unique. I am looking forward to tonight’s season finale. Yes, there were only 3 episodes (again). That’s what I hate about British TV “seasons”.
It's also what I like about British TV seasons. They go on long enough to tell the story, without spinning out an endless soap opera. If TV series were books, the British “books” would vary in size from novellas through to trilogies. North American “books” (I include Canada here) would all be trilogies — with two books worth of soap opera for every book of substantive plot development.
That said, I also agree with you. When you get a good program, the season's over just when you've whetted your appetite for more. (Bearing in mind only the good programs make it to this side of the pond.)