Nice list. +1
I don't know if 4 Assassin's Trophy is correct here. I'd prefer at least one Thoughtseize. Also, with Assassin's Trophy, expect to see it in many, many..... many decks. That being said, it's not unreasonable to go up to 4 or 5 basic lands. I personally run 2 Forest, 2 Swamp, and one Mountain. I expect a lot of Abzan, Rock, and Jund decks to swarm the meta early. BUG may even make a strong case now with Trophy and Push being enough of a removal package to make a case for BUG Midrange in modern.

If you ARE going to run 4 Assassin's Trophy's, what's the Maelstrom Pulse for??

As for your sideboard, 1 Surgical Extraction is plenty. And 3 Fulminator Mage?!? I don't see it being a thing after Assassin's Trophy hits the scene. More Damping Sphere for Storm and Tron. Abrupt Decay for those BUG and UW/x match-ups. And Grafdigger's Cage for those Abzan Company decks.

@Chasmolinker Thank you for the feedback! You make some very valid points and definitely gave me some things to consider. Just out of curiosity how many of Assassin's Trophy would you run?

I'm comfortable with 2-3 right now. 4 just seems like overkill. I would rather see 2-3 trophy and either Decay or Push depending on how much you face versus aggro