hmm... you are running about 15 ramp cards, which is nice. But if you are going to play that many, you can probably afford to cut 1-2 lands.
What you replace it with is up to you, but you could consider
Forgotten Ancient or
Increasing Savagery.
Venser's Journal doesn't really fit in with the theme of the deck.
Nyx Lotus gets the most value in mono-colored decks; here it takes a while to get out and doesn't even yield that much mana.
Izzet Locket costs three mana and only produces two colors.
I recommend you replace these cards with either
The
Signet Cycle: Izzet Signet,
Simic Signet,
Gruul Signetor the
Diamond Cycle: Fire Diamond,
Sky Diamond,
Moss DiamondSeek the Horizon is good.
Explosive Vegetation could be replaced with
Cultivate.
Journey of Discovery could be replaced with
Rampant Growth.
Azusa, Lost but Seeking might seem like a great card at first sight, but by the time it hits the battlefield, you will have little to no lands in hand to play. This card can shine in landfall themed decks and
Lord Windgrace decks, but Azusa doesn't do a whole lot here.
Bloodwater Entity is a card that is best in storm decks (storm is a deck archetype that rewards casting tons of spells each turn). I would replace it with
Nova Chaser.
Air Elemental and
Cloudkin Seer are kinda boring cards
I might replace it with
Cavalier of Gales and
Tectonic Giant.
Lastly, you could replace Parcel Beast with
Mulldrifter, but both work pretty well either way.
Good luck!