I think the publishing requirement is a good one regardless of impact factor. As a PhD student, publishing their own work should be a part of their training. You cannot survive in science without publishing. As a student, it is more about the exercise of publishing rather than the impact of the journal.
I agree with this wholeheartedly, but the fact is that some research groups are much more efficient at publishing than others. I finished my PhD with only a couple of publications, in decent but not fabulous journals. But the reality is that I was working almost entirely on my own, with very little help or input from my advisor. It wasn't training, it was being tossed in at the deep end and expected to swim. The flipside, of course, is that I came out of my PhD functioning at a much higher level than many of my peers who have more impressive publication lists.
On the subject of US vs UK PhDs, this is an issue that I have very conflicted feelings about. I think the US system, when it works, does seem to produce PhDs who are more invested in their own research and better prepared to be independent researchers. When it doesn't work, though, it wastes colossal amounts of time and produces people who are bitter and cynical and either abandon research entirely or go on to torture their own grad students. The UK system is a bit kinder, I think, and doesn't interfere as much with people getting on with their lives.
The comparison between me and my British officemate is pretty stark. We're almost the same age--she's actually a bit younger. But she finished her PhD and started a postdoc two years earlier than me, and she and her husband own a house and two cars and just had a baby.
On my more depressed days I sometimes think that I've got the worst of both worlds by doing an American PhD and a UK postdoc.
