First, sorry 4 me bad english.
1) Make a 2vs2 team with a friend and play 10 matches per week and save the arena points. Buy [item]Merciless Gladiator's Shield Wall[/item] (1650 arena points) or save them for the Season 4 and buy [item]Vengeful Gladiator's Shield Wall[/item]. The shield is the more important piece for me.
2) yes, [item]Girdle of the Fearless[/item] is a good choice.
3) totally agree. take the t4 head but dont forget to loot [item]Warbringer Handguards[/item] >> [item]Iron Gauntlets of the Maiden[/item].
4) I fall in love with [item]Commendation of Kael'thas[/item]. Take it.
5) [item]Slikk's Cloak of Placation[/item] fits well with +120 armor, +2% threat in gloves (I prefer this because scales with gear).
The talents you have are the same that i use until ROS. then i respecced to have imp.shield wall and imp def stance.
The gems i think that are OK. In the beginning I goes for sta gems. When i reach 15K unbuffed i slowly change sta gems for avoidance gems in the new items that i loot.