{advice/opinions}standard G/W

Looking at your mana curve and the cards in the deck, are you content with giving your opponents T1 and T2 to act? All your one-drops are non-creature spells, and you only have four two drop creatures (I'm not counting Boneyard Wurm, because you can't play it until you have creatures in your graveyard).

What about some one-drop mana producers, like Avacyn's Pilgrim, or a mana recycler like Arbor Elf. Use them for mana early, and then use them as chump blockers to fill your graveyard.

That said, you're only playing one Boneyard Wurm.  I prefer to see more multiples in decks because it increases the odds I'll get the cards I want/need for a win condition.

Serra Avatar looks good on the surface, but I normally recommend against it unless you are running a lot of lifelink.  With a couple of Thragtuskand some Nearheath Pilgrim, you'll have some lifelink, but not the amount I'd want to see if running Serra Avatar.  You're not going to want to block with your Pilgrims if you're going to rely on their Soulbond ability to make Boneyard Wurm bigger.  Why not add some one-drop lifelink creatures, like Trained Caracal.  That way, you can get an early start on Lifelink (especially with a Rancored Caracal), and will also have cheap chump blockers to start filling that graveyard.

So, I believe there is potential here, but I believe you need to refine what you have to make the deck a consistant performer.

That's absolutely beautiful!!!

After seeing that Caracal idea, I built a deck around it.  One thing I added you might want to consider is Sphere of Safety. It requires your opponent to pay (1) for each enchantment you control.  If you have Rancor, Ethereal Armor, and Sphere of Safety in play, that means your opponent must pay (3) for each attacker.  Get  another Sphere out and that jumps to (8).

In play testing, I had a lot of fun with it.  My one son played Goblin Aggro with Krenko, Mob Boss. He got more than 160 goblin tokens on the field, but could only attack with one per turn.  He got me, but it took over 20 turns (all of his goblins had First Strike thanks to Bloodmark Mentor, so that's why I modified the deck to add Serra Avenger).

EDIT: spelling