greatest dimir mill

i like the realmwright + crypt ghast combo, but i would probably swap murder with a doomblade and keep murder in the sideboard, then i'd like to swap out tome scour+ mind sculpt for some more control, like unsummon. but overall a nice idea, i just think it needs some redefining to be great.

If it ia going to be the best mill, it needs to be straight mill.
Here is mine.
http://www.mtgvault.com/dragonwolf7/decks/dimir-mill/

Vapor Snag instead of unsummon?

I don't have much experience in playing Mill but did enjoy your deck very much. That said heres my two cents to help out in making this deck only better.

For starters I suggest swapping out your 4 Mind Sculpt for 4 Mind Sculpt for 4 Breaking // Entering. For the same amount of mana, Breaking will mill 1 more card from the opponents deck. If you decide to splash some Red (which is easy with dual colored lands) you can also make use of Entering giving you another creature to fend of your opponent with, be it one of your own or one of your opponents fatties you Milled. This change will also help you keep your deck in standard for when M13 rotates out as Mind Sculpt is not in M14.

A few people above suggested more control and more Milling so perhaps Psychic Strike? Counter target spell is a good deal as its blues source of removal, and is more solid removal then Unsummon which returns to the owners hand. The kicker of Psychic Strike over other counter spells is simply that it mills for 2. ^^ In the slot of Unsummon you can also opt for a little bit of flexibility with Far // Away. Far basically being Unsummon for 1 extra land and Away being extra removal topped off with a reasonable Fuse cost.

While most likely not a competitive option but more so for casual play (depending on the playgroup you play with and the speed of your deck) perhaps Lord of the Void could be a viable option. As a 7/7 flyer he's already a large threat. Once you hit with him you exile mill for 7 and get bring one of the milled creature cards into play under your control. ^^

I do like Duskmantle Guildmage as a sideboard option for your deck. I see its first ability as a tad pricy considering you need to mil before hand. It does work well with Dimir Cypher mill cards however since Cypher requires you damaging the opponent to then activate the Mill effect of the cyphered spell and then deal damage with Duskmantle. As for Duskmantle's second ability, 4 to mil 2 cards isn't bad while top decking i suppose, especially how you can stack it if you have 8+ mana which does seem possible with your deck. All that said if your going to consider Duskmantle Guildmage then you may as well as also look into Millstone. While not a creature it mills the same amount of cards and Duskmantle secondary effect for a lesser more flexible mana cost. While the mill isn't stackable it is a more realistic cost to play throughout the game rather then only when you have 4+ mana open. It also allows you to be flexible with your instants now that I think about it... end your turn with Millstone in play untaped and Psychic Strike in hand and let your opponent take their turn with the option to counter a spell and get off some Mill, or just Mill them for 2 mana at the end of their turn.

Being I'm a combo player Ill leave you off with some funny little potential combos. Being your running Realmwright
you can make your lands additionally whatever color deck your opponent has and run Nightveil Specter enabling you to cast their spells Nightveil Specter pills for you. While the mill is slow it could work decently with Cypher mill effects. Then theres Strionic Resonator (a real gem for combo players :3) that can combo with Mirko Vosk and perhaps Crypt Ghast if you have enough swaps. What makes Strionic Resonator interesting with Mill however is that it can also double effects activated from Cypher. In addition, it also combos with Lord of the Void, Nightveil Specter, Duskmantle Guildmage, and I believe Elite Arcanist. ;o

Hope my comments helped. ^^