Dual class skills

Once I hit 90 on my dual and headed to get my next level on the passive pdef/mdef (I like mdef :3) checked a bit of the other skills and notice this really nice +20% physical attack/resist for 2 certs it made we wonder if it would actually be worth it overall (pve/pvp/mass pvp/oly), I mean it obviously would help with stun but how usefull it is for the other debuffs?
Whats your opinion on the subject?
Is it even worth when you get a hold of 3 dual certs and can get the 27% pdef/mdef skill?

Once I hit 90 on my dual and headed to get my next level on the passive pdef/mdef (I like mdef :3) checked a bit of the other skills and notice this really nice +20% physical attack/resist for 2 certs it made we wonder if it would actually be worth it overall (pve/pvp/mass pvp/oly), I mean it obviously would help with stun but how usefull it is for the other debuffs?
Whats your opinion on the subject?
Is it even worth when you get a hold of 3 dual certs and can get the 27% pdef/mdef skill?

I just had same doubts. But i was unsure what does that physical attack means, cuz it's very confusing. I dunno if its basic p.atk or whatever else.

Physical attack means physical debuffs like stun and knockback.
Here: http://www.lineage2.com/en/game/patch-notes/goddess-of-destruction/character-changes/
Under resistance to mesmerizing debuffs you can see which are the physical and the mental ones.

Thanks for info. Well getting that skill of course benefits you, but +6% pdef, m.def suits tank more I think. There are other ways to boost stun, for example ceremony of chaos earring. And 97+ u can enchant stun skill.