I love this kind of deck. Simply love it. It's my Extended deck of choice, so I know a thing or two about the build.
First: Bottle Gnomes should be on the sideboard, against the aggressive red decks. Why? Because Harbinger is "equally" big, and you can open some space for Chameleon Colossus, which IS awesome. Then, you need Thoughtseize. It's amazing, helps a lot AND you can make for a HUGE 2-turn Tarmogoyf if you hit, say, a Tribal Instant.
Then, you need Birds of Paradise, since it means you can accelerate to a 2-turn Doran, and that's game most of the time.
I'd play Terror over Inversion, even knowing Inversion is Tribal, because Terror can kill Mistbind Clique, and that IS an issue in Standard.
Imperious Perfect could also be used, but not THAT necessary, I'd run Hypnotic Specter over her any day.
And might I suggest... Profane Command? 2, perhaps?

But anyway, DO keep working on the deck, it's awesome, and really fun to play (Btw, I'd TRY - not tried it yet - cutting the Harbingers for Glittering Wish).