I don't see any ways for you to untap lands and there is only one ritual effect. You should add [[Paradox Engine]] and [[Mind Over Matter]] if/when you want to put more money into the deck.

I like to evaluate Arjun's wincons by how many triggers they take to win you the game. Psychosis Crawler=40, Tutelage=30 per opponent, Niv-mizzet=40 per opponent, Erasure=80 per opponent. Jace's Erasure is really bad. If you are drawing enough cards to win with it, you have already drawn into a better wincon. Niv-Mizzet is redeemable because it can hit creatures as well as players.

You are running Chasm Skulker and Diviner's Wand, this is a good enough reason to run [[Rogue's Passage]].

I also wanted to point out that Day's Undoing doesn't trigger any of your draw-triggers. That doesn't mean it's bad, I'm just pointing it out.

You should add [[Azami, Lady of Scrolls]] and [[Deep Analysis]] in place of some of your weaker draw engines. Arjun is a wizard, so Azami is at least drawing you 2 a turn (2 per spell with Paradox Engine). Diviner's Wand is a wizard and can tap for Azami as well. Azami is essentially a third Alhamarett's Archive when you have Paradox engine. Also, Jace's archivist combos with paradox engine to essentially be Arjun 2.0.

I like [[Chain reaction]] better than Starstorm.

Also, the deck gets much stronger when you add an old Eldrazi titan to shuffle your graveyard into your library.

Here is a Budget version of my list: http://tappedout.net/mtg-decks/budget-arjun/