I would suggest leaving the power level, and ability as it is (although being able to remove adrenaline would be a HUGE plus) and making the weapon untargetable. That way it's only counter would be immortality, instead of it also being susceptible to steals, deflags and creatures with destroy.
I wouldn't like that at all. Every weapon outside from weapons from other have something that makes them different from the rest. Arsenic has poison, Discord has quanta rearrangement, Gravity has momentum, earth has perma control, life has healing, etc. However, the only thing that makes the light weapon, Morning Star/Glory, different from the weapons from other is the fact that it comes in immaterial. I'd like to keep morning glory the only weapon that doesn't need a 2 card combo to have immortality.
Plus, wouldn't that be a little too over powerful? Making a weapon that could shut down any deck that relied on abilities unless they had either an Anubis or Quint seems a little too powerful.
I personally, would like its power to be increased to 6.