Definitely want some Abzan Charms here. It can be a kill spell, a draw spell, or even support for the counters theme you have going on.

Siege Rhino is great for all types of Abzan decks,simply from the pure value he provides just by entering the battlefield.

Chronicler of Heroes, Ajani, Mentor of Heroes, Heroes' Bane, and Fleecemane Lion are some other cards you could consider. I'd probably drop the Runemark and the Snakeskin, those Auras are kinda mediocre.

have you considered running Mer-Ek Nightblade

Personally I would take out some stuff and throw in more lands

I have considered it and feel as though I'd prefer to focus flying/lifegain and wouldn't know what to substitute.