Part of it is the massive improvement on the part of the competition. The Telegraph/Times/Guardian sites are significantly better than they were five years ago.
Another shift is widening the target audience. Like it or not, a large number of people who use the internet for news are attracted by more trivial, light-hearted stuff as much as they are by straight, serious news coverage. So there has been a gradual move towards more feature-based content, lighter stories always visible, driven by stats that show that this is what people actually read when they come to the site.
Of course that's going to displease people who just want the straight stuff, but you have to strike a balance between satisfying them and attracting people for the silly stories, who might just stay and read about something heavier.
I should declare an interest here - I worked for a section on BBC News Online over a 10 year period. It was always funny to see the 'top hitting' stories of the previous day, week and month. Inevitably something about a man with three penises would dominate, much to the chagrin of the 'serious' world news journos, whose piece about the Yemen would get about 20 hits.
The point about cuts meaning less imput from foreign correspondents is a good one, though. On the whole, though, the BBC uses its broadcast correspondents better now than it ever did when I was there. For much of the time they basically saw the site as a lower life form, and refused to provide any copy for us. Most of them couldn't stitch together a coherent written paragraph anyhow. The analysis they do provide now is much better.