thussprachal

4 relic of progenitus mainboard seems a bit overkill to me. I would rather mainboard wrath of god instead.

if the main win con is spy/informer combo w/ lab maniac you should run 4 of them (lab maniac) INCLUDING 4 Summoners Pact. the way i see it right now the deck is kind of unfocused, azami, angel of glorys rise, wild cantor and tinder wall, even cabal therapy dont seem benificial enough to ur game plan to be included. On top of that you only have 8 sources of black mana to cast the rituals, so i would put in a few 0 cost artifacts a la memnite or ornithopter to block/sac to informer and mox opal, maybe 1 land to prevent insta loss and cast dread return on maniac, saccing thopters/narcomebas, play the land then self sac informer for the win. another good card would be pact of negation.

I would also suggest running some Preordains, Ponders, Brainstorms, Serum Visions (whichever is cheaper at the moment basically) so you can dig for Sphinx's Tutelage and other enchants you need.

Counterspell is pretty inexpensive. In fact, perfecting this deck within a tight budget would be extremely easy. The first changes I would definitely work towards is running 4 of Sphinx's Tutelage and 4 of Thassa's Devourer (assuming you want to continue down the Enchant Mill route). Cryptolith Rite is a good card but I don't see a purpose in this deck considering how few creatures you run and the average mana cost of cards in your deck. Font of Fortunes is great with Tutelage and is probably another 4 of. I think you see a running theme here...usually, if its good enough to put in the deck, its good enough to have 4 of it. Also, you could justify dropping a land with those changes but that's ultimately up to you.

I always felt like CoCo would be OP in these kinds of decks. Thoughts?

Some cards to consider:

Oath of Jace (+ 2 more sphinx's tutelage),
Memory Erosion
Jace, Vryn's Prodigy

also since you aren't playing in modern you should consider running plain old Counterspell instead of cancel.

I wonder how they would play against each other?

Now all we need to do is make a U/W/R Trump wall deck and pit the two against each other. Vent Sentinel, Wall of Denial, etc.

This deck is basically begging to have Doran in it...if not for all the defenders.

I would personally remove the nahiri and the harmless offering and instead put in donate and some counterspells to protect your demonic pact, maybe a few fog banks as well. Also, persecutor may be a great card but in this specific deck it is terrible as you have no cheap way to remove it aside from path of exile. On that note, silence and path of exile go great with isochron scepter. If you have the money put some tutors in as well to find your demonic pact.

I'm not a fan of guttersnipe, why not delver of secrets? Other than that the deck seems solid, I'd probably run 2 spell snares (hits a lot of relevant targets) and 2 more mana leaks in place of remand, maybe 4 magma jet instead of electrolyze and 1 probe?

You would benefit greatly from more counter spells. My personal changes would be:

-3 byway courier
+1 daring sleuth
+1 reflector mage
-2 odric
-4 thalia's lieutenant
+1 tireless tracker
-3 expose evil
-1 survive the night
-3 jace's scrutiny
-1 fortified village
-1 port town
+3 yavimaya coast

That leaves us with 12 empty slots, of which I would put in 4 sylvan advocates, 4 spell shrivels and 4 confront the unknown (if it's good enough to put in the deck, it's good enough for 4 of IMO). Other cards to consider are Tamiyo, clash of wills, nissa (flip), and for the sideboard graf mole and evolutionary leap.

If you're not on a budget:
Add Consecrated Sphinx?
Add Sensei's Divining Top?
Uhh...splash white with Spirit of the Labryinth, using Aether Vial?
4 Isochron Scepter, 4 Unwinding Clock, 4 Silence?

As for the budget deck listed here, the only card I can think of is Notion Thief (and maybe Teferi's Puzzle Box). Forgive me.

Since Bob is way too expensive, Pain Seer is basically 50 cent ghetto Bob. That and Springleaf Drum would be OP with this deck (+1 exsanguinate) but by then you're running out of card slots.

Otherwise, I would run more creature removal (victim of night/go for the throat maybe) and maybe an extra counter spell and get rid of Wall of Frost and/or sideboard Suffer the Past.

Amen to that.

By the way, if you like trolling...Permeating Mass.

Maybe sideboard in Day's Undoing? Doesn't proc Sphinx's Tutelage though. Also, I don't see the point of Tamiyo if most of your opponent's creatures are going to be stalled AND you have no creatures. Jace would probably be better in the long run, or if you're willing to run creatures Reflector Mage and Spell Queller are good picks.