Spec, I think we have done all we can. We have good handle on PERM data, I-140 filings and approvals, EB2/3 split, EB3->2 porting. We have some data on duplicate filings - some of which may be diluted from porting data. We certainly would like better and concrete data on that.
One thing we don't have data on is demand destruction from people returning or abandoning the GC process, applications left to die by companies due to lay offs, mergers changes, people unable to keep their old PDs, spouse PERM filing etc. In this case I believe even USCIS or DoS won't be of any help. The only thing that can help is forward movement of dates and the filings reflected in the I-485 inventory. We may get a first glimpse at that next month - but it will contain very limited data at best.