Considering you have, unless I missed something, like no mana rocks, 26 lands seems kind of low. I aim for about 33 lands plus mana rocks.
There are quite a few draw commanders. Generally I think
wheels. So cards like
Nekusar, the Mindrazer, every Niv Mizzet ever except
Niv-Mizzet Reborn,
Arjun, The Shifting Flame,
The Locust God, Mizzix of the Igamagus, if you really really want, but I wouldn't use him. Probably more. They all weaponize card draw in one way or another. Not so much Mizzix. Personally my favorite is
The Locust God because he can avoid commander tax fairly regularly. Cast
The Locust God, they destroy it, okay. Cast it again next turn, with ideally one more mana than before for that
swan song or whatever. If they don't destroy it, then you can combo off. I run him and there are no combos like you have with drawing you're entire deck, though that would work, I guess. I just wheel away using just about every wheel in izzet colors.
Wheel of Fortune,
Time Spiral,
Time Reversal,
wheel of fate,
Memory jar,
Magus of the Jar,
Magus of the Wheel,
Tolarian Winds,
Collective Defiance,
Jace's Archivist,
Winds of Change, not Timestwister, I'm poor. Those are the big ones that come to mind. I also have Mana echos,
Phyrexian Altar and
Ashnod's Altar to make mana out of my locusts and continue to cast the cards I draw.
I don't wanna explain my deck too much in case you don't care, so I'll wrap this up.
My friends like it because it doesn't combo and win. I just keep drawing until I either win, or have a bunch of locusts and fizzle out. I will definitely create a board presence if I am able to untap with
The Locust God, but it is fair. I like it because unlike a combo deck, I am not winning the EXACT same way every time. Sure same idea, but win with different cards in slightly different ways, still gets dull after like three games for me.
My friend had Alhammarat's Archive out one time and I milled him to death with wheel effects
T'was great.
Now it doesn't seem like Wheel is the way you are going, but I definitely think that is the best way to do it. But if you want a combo deck and not necessarily a Niv-Mizzet deck, go for it man! The last thing I would ever want is to tell you you're playing/building the deck wrong.
Niv-Mizzet, Parun is a better commander in a lot of ways, but the mana cost is a problem. You can't let a combo deck stall out because your available mana turn 6 is UURRRR or UUUURR. Even if you want to wait until you can combo the turn you play your commander, having a less restrictive mana costs still helps.
Depending on budget, I would replace some weaker counters like Cancel, Essence Backlash, and Mindswipe with combo protectors like Force of Will and Pact of Negation or better value like Mana Drain. But, those are a bit pricey.
On the other hand, dropping spells like Invoke the Firemind and Blue Sun's Zenith (because you have no way to make infinite mana and Omniscience will treat x as 0) would make room for the deck refillers.
Removing some big creatures like Dragon Mage and Thundering Djinn also makes room, and they can be replaced with some basic ramp like Wayfarer's Bauble and Burnished Hart to speed up the deck.
It's also important to add targeted removal like Chaos Warp and Reality Shift, for which you could remove Thought Reflection because it's too expensive and Venser's Journal because you want to reload your deck, not have a 100-card hand.
Another idea is running an eldrazi like Ulamog, the Infinite Gyre or Blightsteel Colossus to get an automatic graveyard reset on discard.
To piggy back on this, I try to keep all my counter spells below three mana, meaning a card like
arcane denial is the worst my counterspells get. You could argue it is better than
counterspell (which I also run) because it is UU, and I have found that blue is very valuable mana. If I had
force of will, I would run it, but I don't and I don't think it is worth investing in. I am suspecting a reprint in the future, but if it is modern horizons 2.0 (if that ever happens) that'll definitely make the price
jump, not dip. Definitely get
Pact of Negation if you can. And
Force of Negation, though I have only used that one once.
Swan Song is also AMAZING!
Turn Aside is pretty decent, as the main purpose of counterspells is for protection.
Rewind is iffy. I have run it without ever using it, while it seems to be great for my friend's Baral deck.
Red Elemental Blast and
Pyroblast are worth considering because blue is a stupidly annoying color. Also instead of
Thought Reflection, which I agree, is too much mana, maybe Alhammarat's archive? More money, but I love it. It turns a card like
Mindmoil into actual card draw instead of card filtering. But I didn't see
mindmoil in the deck list. Still awesome though.
For ramp, I wouldn't do Burnished Harp. I run that in one deck, my
Kozilek, The Great Distortion deck (because you take what you can get in colorless ramp) and I hate how slow it is. Although I admit, I don't know of a better replacement in Izzet.
Gilded Lotus is pretty slow and
Chromatic Lantern is worthless in two colors. It is basically
Manalith.
Arcane signet would make a fine addition after tomorrow.
Fellwar stone would also be decent since at least one other person is playing blue.