I have been playing a disc priest recently in 2s and 3s (friends account)
Im going to explain a few simple tips for surviving arms warriors in pvp
1. Start with all buffs for obvious reason
2. Arms warriors gain Taste for Blood - Spell - World of Warcraft from there Rend - Spell - World of Warcraft . Now here is 2 tips for this (i) try and time your PW:shield or other absorb to absorb the rend tick if possible as this will cause rend not to proc taste for blood (ii) Do not cast when they have taste for blood buff up (try to use instants PW:shield renew ect.) as them overpowering your casts causes Unrelenting Assault - Spell - World of Warcraft This stacks with MS and causes you to only do 25% healing
3. When a warrior starts moving away from you (and not towards your partner) they are most likely backing off for a charge. move with them to prevent a slight amount of damage (longer to get in charge range) and do not cast Penance - Spell - World of Warcraft or other channels with CDs as it will interrupt it wasting the cooldown
4. When a warrior switchs to Shield and Sword or goes into zerker stance (animation of a angry dwarf above his head) he can interrupt your casts with Shield Bash - Spell - World of Warcraft or Pummel - Spell - World of Warcraft so try not to cast infront of him
5. Very Good warrior will wait for the next rend to be just about to tick when they use overpower negating 2. But most will not
Thank you for your time any mistakes ect. please dont hesitate to tell me