There even were tries to make balanced +10 weapons, honestly.
Somebody posted something about a "Hackmaster +10" some time ago. It was a killer weapon, but had a 10% chance of vorpal hit on self
so it would be a last resort.
Said helmet of course is a bit too powerful and probably was made out of annoyance of mind flayer battles, but BGT in general adds almost no new items and the few it does may be powerful but do in no way compare to SotM or the Cloak of cheese
