im new to wow and i start playing rated arena has a sub rogue some days ago and managed to get 1200 CR, and i have some questions in my mind like

1: why people like focusing ret paladins? he has, Shield of vengeance, blessing of protection, divine shield, lay on hands, and word of glory heal a lot of health (btw im the only one who feels that this class is braindead).

2: what is the advantage of a resto shaman? AoE heal is worse then single target heal in arenas, like holy paladins have more defensive CDs then resto shaman and heal more.

3: who is the easiest class/spec to kill that i should be focusing?

4: how do i play healer dps vs healer dps has a rogue? i already played disc priest, sub rogue vs disc priest, arms warrior, and resto shaman, sub rogue vs ww monk, resto druid and the enemy healer just dont let his dps die, then i run out of resource and i lost