arena weapons are supposed to have resilience thats what makes them different from normal PVE gears. if you dont want resilence buy normal items . arena items are for pvp .
Before update Barkskin used to increase physical def by 1% every skill lvl (max 5% at lvl 5)now at Lvl 1 Barkskin increases all defences (physical and magical resistance)by 3% and additional 1% every skill lvl i.e max 7% phy def and magic resistance at lvl 5.