Misterbiggs

After adding in the shock lands, you should be set. If you're not going to do that, there is always a better card than farseek.

Since this is Legacy, consider Clickslither. Great card that works with goblins IMO.

This is a very slow working deck. Without the perfect hand, opponents running aggro will be hard to stop.
Stopping aggro would require a starting hand with Leyline of the Void/Tomrod's crypt, web of inertia, a dark ritual and at least 1 of each colored mana. Keeping in mind that's only to stop aggro from getting to you early on.

I'll definitely try this deck out though. I do like the concept.

This deck is easily beatable. Simple burn spells or fight mechanics can destroy the Ghast and guildmage, being as they are both only 2/2.
I can only see this being a casual play deck.

Needs a lot more card draw. You don't want to find yourself topdecking. Try think twice (for the flash back as well, never a bad idea) and Desperate Ravings. For desperate ravings, try to have land available in your hand so that you can discard that instead of something useful. That is of course, if you have the land you need on the battlefield.

Otherwise, Izzet Charm and/or Faithless Looting work just as well.

What you want in this deck is a way to get out your entire combo. If your lacking the necessary cards, ponder does help.
The thing about this deck now is that its no longer standard, and its illegal in modern because of ponder. If this doesn't bother you, carry on. Otherwise, consider these additions.

First of all, Priest of Urabrask. With him in your deck, you have infinite mana, therefore infinite shocks.
Harvester of Souls. 6 drop 5/5 (or was he 4/4?) with deathtouch and "When ever a creature dies, you -->may<-- draw a card". Theres your card draw. And just in case you were afraid to mill yourself out, its a may ability.
Runescarred Demon is a 7 drop 6/6 that allows you to search your deck for a card, also has flying. If the card draw isn't helping you out, definitely consider this card for that extra search power.
I understand your running B/U, but consider R as well, for Devil's play. Priest of urabrask + devil's play + heartless summoning = infinite damage (if theres no myr in your graveyard).
"But Tri-color is crazy risky", I know, I know. But thats also why you have fetch lands from your Solemn Simulacrum. And if that isn't enough, add in a Chromatic Lantern or two.

Hope I helped.

Based off an original deck concept by David Sharfman at the Gatecrash Pro Tour

http://www.youtube.com/watch?v=wjZb_TdZ3Bk

Cool deck. If you're not worried about it being in Modern or not, consider adding in Clickslither. Great card for goblins. And I shouldn't have to explain that Clickslither + Krenko = GG

Consider taking out a couple goblin siege commanders for Legion loyalist. Normally legion loyalist isn't all that great because its only a 1/1 and can easily be killed. But with goblin chieftain, you can pump up your loyalist ensuring some sort of survival.

If your running venser's journal and Reliquary Tower for Jace's -7 that you'd use on yourself...don't. Doesn't seem like its worth putting in cards just for one single ability that you may not even have go off. A lot of the time you'll end up sitting on the cards with no use for them.

Since this is modern, definitely consider Sanity Grinding. You'll have plenty of blue cards to work with that.
I like the illusions, but what about the illusions has to do with Mill? Its like you're taking 2 different deck themes and mixing them together. You need to ask yourself what you're trying to do, Mill your opponent to death or kill them with damage? Once you figure that out, strengthen that portion of the deck as opposed to having 2 different ideas.

That being said, I would keep the Jace's Phantasm regardless of which way you take the deck. Always a good illusion/mill-friendly card.

Cloudshift works very well. Not only for reasons like Thragtusk, Borderland Ranger and Armada Wurm, but also for Aurelia. Third combat phase? Yes please.

Its a good deck, but there's too many high costing cards. If your point is to mill, you'll want to mill them as soon as possible (preferably before getting killed).
I get why you put in Jace's Erasure, but if its only to combo with Thought Scour and Jace, remove it. Try and keep the deck at 60 cards, though it doesn't matter all too much.
Since you have a lot of high casting cards, I recommend at the very least 24 lands. 20 is way too little for a deck like this. Also, more swamps. I understand the majority of your cards are blue, but you don't want to find yourself with starved out of black with a consuming aberration and mind grind in hand with no way to play them.

If you do consider taking Jace Belern out, try swapping him for Memory Adept instead, (unless card draw is what your looking for).
Also, consider taking out Stern Mentor. Too expensive of a card for an ability that isn't all that good, (especially if it means tapping down potential blockers to keep yourself alive long enough to cast your expensive cards).

Cards to consider:
Glimpse the Unthinkable
Psychic Strike (for some form of control)
Mind Funeral
Tome Scour
Mind Sculpt
Psychic Drain (for the life gain)
Psychic Spiral (only if you end up running more instants and sorceries than you already have)
Dreamborn Muse (if you decide to keep Beleren)
Riddlekeeper
Hedron Crab

Just some suggestions. I don`t recommend putting them all.

Consider putting in Odric, Master Tactician. It would be useful to have somebody purposely block your indestructible Priest of Penance, or even to just swing all out unblocked.

You're running defender Mill without Doorkeeper? Say why?

Where's Cloudpost? Its a temporary way to get your creatures to flicker when you can afford a restoration angel or a closet.

Ever consider trying Charmbreaker Devils? High drop, yes, but when they get out, tough creature to kill, and they give you your instants and sorceries back. =D

Why not run Unbreathing Horde instead of either the Blood Artists or Geralf's Messenger?
The Horde would become incredibly powerful with corpsejack menace on the field, not to mention how powerful it becomes with each zombie you already control.

Its very well made. Good job.
I was thinking, what about Killing Wave instead of Black Sun's Zenith? I understand that you could easily remove the -1/-1 counters from your creatures, but thats the whole reason they have undying correct? Save your Power Conduit's to remove those +1/+1 counters from your creatures instead of taking off -1/-1 counters. That way, your turns are more effective, sacrificing your creatures for killing wave works easier, and it will still help damage your opponent nicely, all for the same cost as Black Sun's Zenith anyway.

Just something to consider.

Its a good idea. But its difficult to pull this combo off, seeing as Mikaes is a 6 drop. But definitely worth trying out.