Well, as you mention the talisman...
All the other blue weapons are pretty good, too, not only the magic damage staff/talisman.
The 1HB is at least on par with many raid epics or faction weapons. The PoM/ToS staff is superior to T1 to T3 raid staffs/polearms for PoM/ToS. And the list goes on.
So if you nerf them, you'll have to nerf them all.
But first, recheck if this wasn't all done on purpose and with good cause. The weapons are good, but heck, so are the blue armor pieces. That is why the dungeon was well received. Nerf everything to the ground, and people might loose interest again.
Personally, I believe the guy who did the item design is on vacation, and nobody bothered to check with him if this is indeed a bug...