Spell penetration does nothing in PVE. At all. Ever. It is a good PVP stat and nothing more.
Boss level mobs have a 5% partial resistance to non-binary spells (i.e. those that can be partially resisted). This resistance can not be overcome with spell penetration or hit percentage. [note: This particular mechanic is still undergoing testing, some bosses appear to violate this rule].
Is it absolutely confirmed spell penetration does nothing in pve? don't some bosses have partial resists to fire or arcane and so forth?
Further, the two statements seem a little bit of a contradiction.
please discuss whether spell penetration is useful in PVE on level ?? bosses.