Squadron Hawk is best card of this generation, and all other generations.
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If you're looking for some more damage, I would recommend Sanguine Bond, as the lifegain you have will cause you to seriously nuke the opponent at the same time. Though I'm not a fan of the Sorin's Thirsts, they would become significantly better with the use of Sanguine Bond. Another option for you is the much older card Siphon Life, which can be retraced and can also target players. I will however say that your Blood Tribute has a much smaller range of usefulness than your Corrupt, despite being similar effects. Blood Tribute is likely a much better sideboard card, especially if you come against other lifegain decks, but Corrupt is usually a better option, since it scales with your land as opposed to your opponent's life total, AND corrupt doesn't require a kicker to give you the lifesteal. If you can get your hands on another Corrupt, I'd put it in place of the Blood Tribute. Also, if you can get your hands on Sorin Markov, it'd be fun times for all.
Just chiming in to say that those terramorphic expanses that you're running probably aren't helping you much. They really only give you an automatically tapped basic land when you play them. I would run Cultivate and a few basic lands instead of those. Alternatively, you can run a Rupture Spire to get a mana of any color of your choice on the following turns, or play Sakura-tribe Elders if you need to chump-block some goblins out of your friend's deck (you can sacrifice them after declaring a block and put a tapped basic land on the field from your library). Also, there's a green spell called Overgrowth that I've toyed with, it enchants a land to give GG whenever tapped, in addition to it's normal ability. There's also the Vivid [Land] series, can generate its color anytime, or generate a different color twice. Also, the Golgari Signet would be good for you. I guess what I'm getting at is that Terramorphic Expanse is bad, there are a lot of better options for you if you need to pick specific-colored lands. As far as creatures, I would trade out those Tormented souls for several Child of Night(s), as they're a good, cheap blocking option in addition to having lifelink.