My first thought is that death-by-drawing and mill are two different strategies. If you're going mill, I think some sort of combo is needed, as using mill effects one at a time on 3 opponents is just too slow a way to win. Either Shaarum & Phyrexian Metamorph, or Sword of the Meek, Thopter Foundry, and Ashnod's Alter create infinite creature death triggers, which combo with several things (look at the Gravestorm cards from Future Sight) to mill infinitely. If your strategy is to win by forcing people to draw, which is what your commander is for, you shouldn't count on people running out of cards in their library, but instead have redundant hurt-to-draw and draw-more effects. I haven't seen it done but some sort of Stasis or Stax (stax is cards like Smokestack and Braids and Shattergang Brothers that force everyone to sacrifice a lot) effects would pair well with a lot of forced draw since it fights back the tendency of your opponents to draw winning cards when they're drawing 2 or 3 extra per turn and haven't died yet.
I'd be careful with your 1-for-1 counters and removals. In a 4 person game if you spend one spell to counter or remove one card of an opponent's, then the other two players both come out a card up on the two of you. Not saying Murder and Counterspell shouldn't be in there, but the bar on what a good 1-for-1 is higher in multiplayer.
If you're going to have only 17 creatures, then some more whole board removal are definitely a must. At a minimum I'd suggest Wrath of God, Pestillence, and that new one from Commander 2013 that costs three mana and x life and gives all creatures -x/-x. Terminus is a very good idea for this deck. From recent experience I can say that Sphinx of the Steel Wind is brutal in these colors.
When you're in black, it never hurts to throw in a few more tutors. If you can get a few more scary blockers (the strixes are a nice addition to nighthawk. Wall of Denial and Fog Bank are pretty awesome) then original Liliana is one of the best commander planeswalkers. Both Tezzerets are good in Commander as well, and I seem to remember you having those.
And then there's the matter of land. Land is the bitchiest card type in the game since it's where there's the most direct correlation between card quality and price. My first suggestion is to start dealing drugs and buy Revised duals and Onslaught / Zendikar fetches. More realistically, the Shocklands (2 damage to come into play untapped like Hallowed Fountain) from the two Ravnica Blocks and the Checklands (come into play tapped unless you control the related land type) like Glacial Fortress combine really well. If enough of your land comes into play untapped, you're basically a whole turn faster.
Right now I think your biggest worry with this deck is playing against some aggro big creature deck and pissing them off. Ghostly Prison and Propaganda are good defenses against this, especially if you're worried about token aggro. Humility is a good way to put a stop to a board full of dangerous creatures. It's also a good way to lose friends and get confused by the rules, so maybe not.
Phyrexian Arena should be in this, along with Rhystic Study. I'd lose some of the cards that draw a fixed 2 or 3 cards, and replace them with draw X effects. Blue Sun's Zenith is a must if you're looking to kill people by making them draw cards.
I'd also suggest some more artifact mana acceleration. I usually try to go with 45 land + 2 or less mana artifacts & creatures, and then 2-5 more expensive accelerants. If you're running Rite of Replication you do not want to stall out at 6 land, and you probably want to be at 9 well before turn 9. Signets and Talismans are your friends. Fellwar stone is your friend. Mana Vault may or may not be appropriate. I'd suggest getting a hold of a Strip Mine, I think it's the second card that should be in every single Commander Deck after Sol Ring. I am totally blanking on the name of the land that prevents combat damage from one attacking creature for 1W. But get it. In a deck that runs enough white, it's better than Maze of Ith.
So yeah, tl;dr is:
1) Pick hurt-to-draw or straight mill and stick to one.
2) Play with more creatures or more boardwipes
3) If your playing Esper and have some tutors, it's silly not to have a combo in there.
4) Re-evaluate some of your 1-for-1 removal instants and sorceries. Go for things that can hit multiple card types and aren't conditional on your opponent not having enough mana.
5) Cards that only draw 1-3 cards one time are marginal. Only go with the best.
6) More and better mana.
I'd be careful with your 1-for-1 counters and removals. In a 4 person game if you spend one spell to counter or remove one card of an opponent's, then the other two players both come out a card up on the two of you. Not saying Murder and Counterspell shouldn't be in there, but the bar on what a good 1-for-1 is higher in multiplayer.
If you're going to have only 17 creatures, then some more whole board removal are definitely a must. At a minimum I'd suggest Wrath of God, Pestillence, and that new one from Commander 2013 that costs three mana and x life and gives all creatures -x/-x. Terminus is a very good idea for this deck. From recent experience I can say that Sphinx of the Steel Wind is brutal in these colors.
When you're in black, it never hurts to throw in a few more tutors. If you can get a few more scary blockers (the strixes are a nice addition to nighthawk. Wall of Denial and Fog Bank are pretty awesome) then original Liliana is one of the best commander planeswalkers. Both Tezzerets are good in Commander as well, and I seem to remember you having those.
And then there's the matter of land. Land is the bitchiest card type in the game since it's where there's the most direct correlation between card quality and price. My first suggestion is to start dealing drugs and buy Revised duals and Onslaught / Zendikar fetches. More realistically, the Shocklands (2 damage to come into play untapped like Hallowed Fountain) from the two Ravnica Blocks and the Checklands (come into play tapped unless you control the related land type) like Glacial Fortress combine really well. If enough of your land comes into play untapped, you're basically a whole turn faster.
Right now I think your biggest worry with this deck is playing against some aggro big creature deck and pissing them off. Ghostly Prison and Propaganda are good defenses against this, especially if you're worried about token aggro. Humility is a good way to put a stop to a board full of dangerous creatures. It's also a good way to lose friends and get confused by the rules, so maybe not.
Phyrexian Arena should be in this, along with Rhystic Study. I'd lose some of the cards that draw a fixed 2 or 3 cards, and replace them with draw X effects. Blue Sun's Zenith is a must if you're looking to kill people by making them draw cards.
I'd also suggest some more artifact mana acceleration. I usually try to go with 45 land + 2 or less mana artifacts & creatures, and then 2-5 more expensive accelerants. If you're running Rite of Replication you do not want to stall out at 6 land, and you probably want to be at 9 well before turn 9. Signets and Talismans are your friends. Fellwar stone is your friend. Mana Vault may or may not be appropriate. I'd suggest getting a hold of a Strip Mine, I think it's the second card that should be in every single Commander Deck after Sol Ring. I am totally blanking on the name of the land that prevents combat damage from one attacking creature for 1W. But get it. In a deck that runs enough white, it's better than Maze of Ith.
So yeah, tl;dr is:
1) Pick hurt-to-draw or straight mill and stick to one.
2) Play with more creatures or more boardwipes
3) If your playing Esper and have some tutors, it's silly not to have a combo in there.
4) Re-evaluate some of your 1-for-1 removal instants and sorceries. Go for things that can hit multiple card types and aren't conditional on your opponent not having enough mana.
5) Cards that only draw 1-3 cards one time are marginal. Only go with the best.
6) More and better mana.