First please don't use AP gems, always str. Simply because AP gems don't get any benefit from blessing of kings.
Helmet is ok but think on saving up and dropping herbalism for Engineering, you get a great dps helmet plus a tanking helmet and the gun if you want to level all the way up :P.
Run Durnhold (normal) and get Mantle of Perenold, upgrade is Chess shoulder or Arena S2 shoulder. Yes leather is ok and chess shoulders > Arena by a small margin.
Enchant your chest +6 to all stats and more arena for S2 chest . You can use S2 chest for tanking as well .
Cloak of the Inciter or better yet buy/craft Vengeance Wrap .
Go on AH and buy Fel Leather Gloves and Fel Leather Boots, they're cheap and the best you can get until 25man. Nightbane plate boots are not better until you can sustain 200 hit rating with them. And those blue boots are better than the Ogri'la epic rep boots.
Just way to good .
Hourglass of the Unraveller and Abbacus of Violent odds are superior trinkets, get them .
And put a dps patch on those pants . Run heroic SP or Mecha for epic dps legs.
Fel Leather Gloves/Boots are the priority for you .