Red aggressive is one of the hardest matches by far. Matchup is bad G1 but gets better post-board with Surge of RIghteousness, Ultimate Price, Arashin Cleric. While PW Jace is okay against aggro, I tend to board him out in favor of Ojutai simply because he usually dies to Wild Slash immediately in his creature form. Even at his best, he's mostly win more; whereas, Ojutai just wins if you can get to him at a reasonable life total and board state. He also provides another source of life gain via Sorin's +1.

Cool.  How much have you played against red aggressive decks?  That seems like the toughest matchup.

Well, Ugin was cut eventually, though not for your reasons. Quite frankly, he was just too slow overall. With removal and card draw being what they are right now, the deck rarely has time to wait for Ugin. Moreover, there are a few too many threats commonly played in the format that he can't deal with. With his removal it felt safe to cut a land. Right now, Ugin's former slot is occupied by Narset, who's been okay. I may swap her for a third Gideon though. Gideon has been very good in tandem with Sorin but just solid without. Perhaps the correct swap is the second Ob Nixilis for a third Gideon? Ob's been about as effective as Narset overall thus far. Other than that, Sorin and Gideon are the primary win conditions. Ob Nixilis, Awaken lands, and Shambling Vent are the secondary ones. Jace is a tertiary one.

Do you really need Ugin if you have Planar Outburst, Utter End and Statis Snare?  What if you went with a 3rd Gideon (he's your win condition) and lost Ugin?  You'd probably be able to cut a land that way too.