Greetings AylinIsAwesome and welcome to the forums!
The first feedback I have is that you have a very tall order ahead of you if you are seeking a curse focused build. I don't think the cards are there yet for this to be a very effective style of play, but it is certainly a fun one! The bigger problem is that you are facing creature heavy decks and want to counter them with a curse heavy deck. I don't think that will work very well in your favor, unfortunately.
The main problem, as I see it, is that you would fall behind quickly spending all of your actions and mana on curses on the creature heavy builds coming at you. Considering that curses aren't instantly effective at controlling threats, you are falling behind with no immediate gains to show for it.
Looking at the cards you have in your book, however, tells me a different story. I see a nicely rounded deck that isn't relying on curses. You can have a beastly geared mage to battle with, with several Big Bads that you don't need all of them in play to really deal the damage. I think this is a winning strategy and I wouldn't try to shift into a bigger curse investment of cards.
Some thoughts:
You have a Pentagram and a Battle Forge. I would argue that you only want one of these action granting cards. Casting two of them takes so long to break even on mana spent that I believe it to be a losing move. Also, as has been discussed in the Spells forum, the Pentagram is weak. It is easily the worst spawnpoint, and I do not use it. The Forge is quite nice though, especially with the amount of equipment you are packing. Pentagram for Deathlock is a winner, I think.
I would consider doubling up on the Helm of Fear. You mention you are facing creature heavy decks, and thus the Helm of Fear becomes hugely important. If I were facing you with a creature focus book, you would simply not have a Helm of Fear on the table. Prepare for that and have a backup or two. Simularly, Demonhide Armor can really do a surprising amount of damage against swarms and would be a priority card to remove. Not sure I'd double it, though.
I would drop the skeletal sentries, and one of the demons. The sentry's immunity to the Idol of Pestilence doesn't outweigh the fact that they are a poor creature, in my opinion. You will likely only want to Blood Reaper once in a duel, and I find the Dark Pact Slayer the superior demon to the Hellion for Reaping. Important to note here that I have not received my expansion yet, so the Psychic Immunity might have far greater value to you than me currently.
I personally would run more anti-equip cards, too. There are too many priority equipment cards, and a geared mage is very scary.
As much as I try, I can't really justify the cost of walls. The Walls of Fire could be better served as more attack spells. This would make the Fireshaper ring nice to have too, though if you want to move away from the Lash I can see it not making the cut (there is some Sectarus pun here if you squint just right).
You have no Drain Life spells, which like Explode, give you two abilities in one action. They are crazy expensive, but I find them so very powerful as the warlock.
Chains of Agony I skip, and most times Agony too. They are just not helpful enough compared to so many other cards that would take that action and mana. Consider the more curses you have in play the less effective your Curseweaving is too. And believe me, you want to keep Death Link going. And Ghoul Rot.
4 Nullifies might be overkill. Consider you have so much equipment out that it sorta protects itself to a point. You cast Sectarus and I plan to melt it. But you also cast the Demonhide Armor... now I have to choose, etc etc. I personally love a geared mage and count on having a target rich environment for my opponent. They can't melt them all!
These are just some random, off the cuff thoughts I had. Usual disclaimer here that I'm not an expert, and am sitting at my desk 'working" so I take it for what it's worth.
