Looks like a pretty great deck. However, I would suggest dropping fire at will for lightning bolt. True, it is only red, but the cost makes it worth it. Although battlegate mimic becomes slightly less effective, Belligerent Hatchling becomes more useful when you have more cheap cards to play quickly. Even though fire at will will make hatchling lose two counters, it costs three times as much to cast. Three mana is extremely costly in a deck that doesn't have access to much mana. Lighting bolt will be useful both early game and late game. Fire at will is useless early game and, although useful later game, will leave you very short on mana.
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Also, replace coat of arms with another immaculate magistrate. It's essentially the same thing, only you can use immaculate magistrate over and over again. Also, I'm really trying to understand the purpose of bountiful harvest, essence drain, and fog. Elves are highly offensive. You shouldn't be worried about your life, just your opponents. Also, might of alara is pointless, considering there are far more efficient and permanent ways to increase your creatures power (immaculate magistrate, for instance). And one more thing: If you're running green/black, you have access to the greatest elf in existence: Nath of the Gilt-Leaf. Get some of those in there.
It's pretty heavily green, you could just go mono to avoid mana issues. Also, replace some of your mana with treetop villages and, particularly, gilt leaf palace.
Did you read the description at all? The whole point of this deck is to get the powerful creatures out first. I use dark ritual, llanowar elves, and llanowar mentor for that. Furthermore, this deck has massacred two of my friends mono-green elf decks.