Ulamog is super redundant, IMO. You already have Repeal, you already have Eldrazi, and you have planeswalkers. I very much doubt any deck would be able to come up with a comprehensive way of stopping all of those. I just went infinite this past week with no Repeal against a "burn" player who ran Ensnaring Bridge main. Even with absolutely no way to get rid of the bridge in the main deck, Emrakul still lets you take all of the turns, and I pinged him out with Ugin. I may put Repeal back, but with Ugin, there's even less of a reason for Ulamog to be there.