data and analysis

Ah, I see your point. Knowing the malady better will help to tailor a better solution. You got my attention, in particular, with where new editors are being reverted--stubs, long articles, and so on.

Do the other task force members have contacts/ideas along these lines?

I'm not sure. You could ask them. Part of the problem of being a veteran is a lot of your contacts end up being at least intermediate level, and it's hard to get more than a few anecdotes about the experience of new users. But if someone knew how to sort out some 1-shot users from 2009, and some other 10-100 edit users from a similar time period, I'm confident I could bang out an analysis pretty quickly. You'd just need a random sample of 20, and a quick comparison of their edits. I've seen pages like this. But it would be much more interesting to look at new users who survived, and compare them to new users who didn't. It would also be more interesting to look at editors with more than 100 (or even 1000 edits) who haven't edited recently, and look at their last slew of edits.