(I think Barbed even cripples for longer period now [someone confirm this])
Yes it does. I think the idea of this trap, as someone mentioned before, is to keep the enemies in the traps while hte pulses go off. With 5 pulses, dust trap can be extremely deadly, but it's only deadly if you can get them to stay in the trap area. Probably more usefull in PvP, as PvE monsters stay in the trap area anyways...
In a 4-5 man trap group, it works real well if one person brings it. The knockdown/cripple is really useful so the rest of the traps hit them. Although with a good enough group, that isn't a problem. Even so, the high damage and low energy is nice.