Well now our versions looks exceptionally close. I added Charmbreaker Devils to have an extra beasty creature and the card draw he provides. Really he replaces the 4th Urban Evolution. Because Urban Evolution doesn't actually DO anything itself besides allow for a 2nd land to be played the same turn - most likely a negligible benefit unless you're sitting on Elderscale and land. Of course, 3 cards is awesome - but do you need to cast the spell twice?

My answer: No. So it's a great spell, but you want it once, not twice, and the deck isn't built around it. Therefore: 2 or 3 copies is appropriate. Not 4.

3rd Ground Assault? Cool and good card!

But what's better in a land destruction deck?

INTO THE MAW OF HELL

Two for one!!!!! :D

There is enough ramp and cheaper cards to warrant 2 Ground Assaults, and splurging on Into the Maw of Hell, which gets the land destruction job done.

Getting that 2nd red might be on occasion difficult, but with a Steam Vents as the perfect Farseek fetch, it shouldn't be a problem.

Or a stomping ground + Arbor Elf. There's enough mana tutor to have it by 6.

Then there's my "joke" card: Unexpected Results. Chances are in a deck like this you'll actually be happy with what you get. Mana ramp? Great! Expensive card? Great! Tentatively swapped for a Demolish.

Lastly Devestation Tide vs Tamiyo.

Anywho's it looks like we have a pretty good deck going. I like most of your sideboard. I'm thinking a 3rd Elderscale Wurm might be appropriate for those certain tough matches.

I love the concept. Made a few quick changes, it would still need ironing out, but I think you'll like them.

Additionally, several more great ideas in the sideboard.

http://deckbox.org/sets/349833