Regular FL blogger Eric Muller posed a very interesting and thoughtful question in this post Are We Sustaining a VAP Trap? He did not argue that there was a "VAP trap"; he was inviting thoughful inquiry and perhaps reconsideration of whether, all things considered, it makes sense (at least for some) to have such programs or to enter such programs in the current job market.
Here is a great post from Christine Hurt over at The Conglomerate which I think sums up the issue very well. The VAP Debate. The bottom line is that doing a VAP has always entailed uncertainty and is going to be more of a risk in a down market. And it is a down market right now, particularly since so many schools are doing precisely what so many of the critics of the status quo think they ought to do - to wit, downsizing their classes and thus not hiring new faculty.
Professor Hurt reports a few things that bear repeating: law schools pay VAPs, not the other way around, so this is NOT like being a student and not necessarily a cost savings for the school since, although VAPs are paid more than adjuncts, they are typically paid less than regular faculty and do not do any of the associated service faculty are expected to do and sometimes teach fewer courses (programs vary). Most school could get adjuncts to teach the same classes for less money. So the cheap labor thing just doesn't wash.
In the current environment, it may well be that some schools will cut back or eliminate their VAP programs. We will have to wait and see. As many have already observed, not all programs are the same. Some provide more opportunities to workshop papers, more mentoring, etc. than others. The Bigelow at Chicago is a well-known example.
At any rate, go to the Conglomerate to read Prof. Hurt's take on this issue.