You are missing important card draw. You should consider Impulse, Frantic Search and Recurring Insight. Also Treasure Cruise and Dig Through Time work well.

Thanks for commenting kirox317!

We did not want to overdo it with draw cards in this deck; it already has eleven cards towards this end to facilitate us in this. However, Treasure Cruise is in our collection and we will give it a go (we have exchanged it for Reverberate).

Is there a certain reason that you play Lightning Bolt? I know that there exists the infinite combo with Reiterate and a ritual like Desperate Ritual. In my opinion Fall of the Titans does the job better.

Also, as you statet above, you would like to keep the deck fun for your playgroup, so I'd like to suggest a card: Murmuring Mystic

We just felt that an Izzet spell-slinger deck wouldn't be complete without Lightning Bolt. The infinite combo is fun, but overall it's just great, cheap removal. Fall of the Titans could be good in this deck too; we'll have a look at what it would replace. As for Murmuring Mystic; we do not own this card and we're not really in favor of adding more token generation (or replacing our current cards for this).