Antonio Giustozzi is saying that insurgents in Afghanistan (insurgents affiliated with any group, not just the neo-Taliban) now number "in the tens of thousands." A major part of them could be operating from Pakistani territory, nevertheless this is quite concerning.
I remember reading in a book on Kashmir, edited by Sumit Ganguly, a figure from Praveen Swami (on p.51.) that about 3,500 insurgents were involved in the fight in Kashmir at any stage (this comes from Indian intel estimates). If that is true -- and I could not really dispute this -- the contrast is not boding too well for ISAF and OEF. In an asymmetrical conflict, having tens of thousands vs. the actual number of fighting foreign soldiers (the total minus the "long tail"), well, that's anything but numerical inferiority, even with air power counted in with more weight (although at times it looks like the latter may even factor in in a negative rather than a positive way, from a counterinsurgency perspective).