My first recommendation for you is to run more lands. I would suggest running 34 lands. You could add Evolving Wilds , Bojuka Bog , Creeping Tar Pit , Darkslick Shores , Dreadship Reef , Drowned Catacomb , Frost Marsh , and etc.

Cards I would take out for new ones are: Augury Owl - would rather add more card draw than scrying so you can put more creatures or artifacts down. maybe a Mulldrifter .

Circu, Dimir Lobotomist - you would be better served with a Steel Hellkite for removing stuff than this guy also it's going to be random what you hit with it.

Dark Hatchling is okay, but I think there are just better cards out there.

Nemesis of Reason - is a cool card but I don't think you need it. Most of the cool creatures your going to want to use in others graveyards will be killed by people for you because they are powerful. Graveyard manipulation isn't your theme so I would substitute this with something else.

Wall of Frost - there are better ways to do same a thing or better defenders. For example Void Stalker which has potential to shuffle a commander into their library (this could kill shattergang for you). There is also Fog Bank , Gomazoa , and Guard Gomazoa .

Lash of the Whip - i don't like this card at all. You should have a board wipe in your deck over this. But if you want the negative counters you could use Black Sun's Zenith

Stymied Hopes is very easy to stop, with just one mana. For same converted mana cost you could just do Counterspell

Barrin's Spite - I don't like that this card lets your opponent choose. alot of creatures have come into play abilities and could easily make you not even want to cast this spell.

Ghostform - i get why this is in the deck. But it is not an instant which sucks, also if you have shroud on a creature you won't be able to target it; or if you had one of the swords on a creature that gives protection from blue.

Cards I would reccomend - I think pretty much everycard in your "maybe" area would be good.

Oblivion Stone , Nevinyrral's Disk , some board wipes in general.

going out for food so finishing up this part later.