I've been playtesting this deck, and it is indeed really fun. I seem to win more off niv-mizzet + Curiosity. Rarely ever getting a good swan engine going. The manabase needs a lot of work, the Mystic Monastery is a good start, but so far as budget lands are concerned: The Innistrad duals have dropped significantly, Glacial Fortress, Clifftop Retreat, and Sulfur Falls. Temples in standard aren't as high as they used to be, but they should drop even further in a year or so, Temple of Epiphany, Temple of Enlightenment, and Temple of Triumph. Refuges from khans, and the older ones should be almost no problem to get ahold of, Sejiri Refuge, Swiftwater Cliffs, Tranquil Cove, and Wind-Scarred Crag.

More expansive lands (I will try and list them from least to most expensive). Utility lands, Desolate Lighthouse, Slayers' Stronghold, Moorland Haunt. Pain lands Shivan Reef, Adarkar Wastes, and Battlefield Forge. Shocklands, Sacred Foundry, Steam Vents, and Hallowed Fountain. One on color manland Celestial Colonnade The recently reprinted, but still fairly expensive, fetchlands. Scalding Tarn, Flooded Strand, and Arid Mesa.

I think the first paragraph will be more helpful in making a budget land base, but if you plan to play a lot of modern (with this deck or others) the lands in the second paragraph are always useful.

I think that Spellskite could be nuts in this deck. You can protect your creatures while just having a maindeck card to wreck burn and hexproof.

Blasphemous Act? It gets its price reduced from Swan Song, draws you thirteen with just one Swans of Bryn Argoll out and wipes your opponents board as well.

Seal of Fire?

I've played against it, and its pretty annoying actually. Fits great on the curve and they can do nothing against it, since you'd just sac it in response to removal. Also keeps them from playing small creatures until its gone. Like an eternal present Rift Bolt.

Maybe, but what would I replace Willy61?

Great question. I don't know - Maybe Magma Jet?

Have you considered Fatal Attraction as a kill spell/card draw thingy?

I don't mean to answer for the deck creator, but it was mentioned in the comments above.

Dude you got to run Seismic Assault

How did you put the clouds in the title?

What, no Chain of Plasma?

RoarMaster Sadly, Chain of Plasma is not in modern.