It is such a hard, and I think unintended, nerf to Sand Sage and Blood is Sand. The Sand Sage nerf is a huge deal - it is impossible to keep the 15% damage reduction up now, we have no true shroud form to go to so this was the trade off. The all ready minor dmg buff of Blood is Sand suffers from the same issue... its not like DPS scourge was top of the heap. I'm honestly really mad.
I guess you could balance it by giving us 7 charges; they more then halved the duration, but gave us nothing. I would rather the duration goes back to 20, but if not we have to have some way to keep 3 up at a time, all the time.