Corilithon

Come to think of it, Spelltithe Enforcer would make the lock a little harder.

Creature-light control would probably tear this apart rather easily...

And it isn't a hard lock, it doesn't actually stop them from doing anything. It just makes it harder.

Your answer to something like Terror or Hero's Demise ought to be Avoid Fate. It's cheap, it's effective, and it stops things like Tendrils or Terror out of Black, and things like Pacifism or Faith's Fetters out of white. For a more permanent answer there is always the awesome Privileged Position.

What, no Swamp Mosquito? Think about it, with Hivestone the the right slivers it can be a 0/1 flying that gets +1/+0 and gives a poison counter when it isn't blocked, and then gives additional poison counters if it deals damage.

That spells sexy right there.

I think a deck based on the Avatar show would have to be W/U/R/G; Air, Water, Fire, Earth.

You could try Intimidation as well.

You should take advantage of Jhoira a bit too.

Try to get Aeon Chronicler and Greater Gargadon. Both of them go for a little bit of money, but the Chronicler is in the Planar Chaos precon, so if nobody is willing to trade there is always that.

Try to throw in some Mouth of Ronom.

Actually, that won't even work, since the Summons is a sorcery. D:

And I really don't get the Cloudstone Curio. You don't have any good CIP abilities, and you don't have any creatures with flash. Best you could do is Sosuke's summons to save a few snakes, but really...

What, no mighty Shisato, Whispering Hunter? That and Nature's Will are great fun if you can continue to get Shisato through. And you can keep a steady stream of snake meat for him.

Defense Grid will horrifically rape your counterspells, plus it will make you pay the extra mana to play the spell copy from the scepter. I'd advise against it. Delay is good, but if you never get a teferi it's not quite good enough as a counter. Running a Gigadrowse or so might be a goodi dea, as it's a really nice card to lock them down for a winning turn. And yes, Evacuation is good, and though it is a rare it shouldn't be too hard to get, likely easier to get the 9th edition version.

First thing i'd do is reduce the number of Blaze in the deck. Or switch it for Disintegrate, which shouldn't be too hard to find. Get more Seal of Fire, and try to score some more Benalish Cavalry and Soltari Priest. And the Sunhome Enforcer doesn't seem to do too much for you really, try something more effective.

The deck looks way too expensive, with no acceleration to draw out your fatties then you're not going to survive past the early game.

Well, throw in some Tendrils of Corruption. It's great as both Spot Removal and lifegain for when you get into the danger zone. But if you throw in more than one of those then you'd do well to toss in an extra copy or two of Urborg.
This looks a little like someone watered down the Dralnu deck, really.

Firstly, Sprout Swarm is good because it has Convoke and Buyback. You can use creatures (via Convoke) to pay for Buyback. So while it's not a bad card, it's still not a really competitive card.
Secondly, Earthcraft will not make you lose the game because it's an OPTIONAL infinite combo. You're not forced to tap a creature and untap the land Squirrel Nest is on. You would just choose how many times you do the combo, and assume you tapped/untapped that many times.

1998 World Champion you say? But I only started playing in '03! The deck looks scary.
But! Coming out of Standard, Bogardan Hellkite absolutely loves coming into play! 5 as you chjoose divided among any critters and players, plus a 55 flying beater for your trouble.

Stone Rain would be a nice addition to the deck. What's more evil than a turn 1 Bird or Elf, then a turn 2 Stone Rain?
Simian Spirit-guide might speed the deck up a turn, maybe even giving you the elusive turn 1 Stone Rain! Gasp!
Acid-moss isn't bad, it's just a turn later than Stone Rain. Rhada, Heir to Keld might be goo in the deck (I'd replace the Wumpus with her unless you go more LD.) she can get you that turn 4 faceup Akroma, and she's a stronger elf in and of herself!

A lot of expensive things and only 18 land?
Yup. Trim it to 60, focus it, add more land. Then you're set!

And also! This deck is 4 cards away from being T2 legal. Standard! Woo!