While we don't know exactly how Ixalan will play out as a Limited format, we can get started by figuring out which cards you want to start with. Identifying a range of cards you'd be happy to first-pick helps guide your drafts, and there are some nice ones here. I'm going to break them down into tiers and talk about what each tier means. Let's jump in!
These are the cards you will undoubtedly take if you open them. The only one I'm not quite sure about is Gishath, Sun's Avatar because it's three colors. Still, it looks worth building around, and rewards you mightily if you do. The rest of the cards are just awesome on their own and don't require much of you besides being able to cast them. If you open one of these cards, go forth and conquer!
These are the cards you are thrilled to first-pick. The order does matter some here, as there are rares and uncommons both, but for the most part these won't have much competition if you open one. These cards not only give you a ton of power to start your draft, but they also really point you toward a specific direction, as trying to make sure you get to play these is worth the effort.
This next section features cards you are happy taking early. Top-tier common removal, good uncommons, and powerful but not busted rares are mainstays here. If you start with one of these cards, you did well.
Average Early Picks
This section comprises cards you will often take early and don't mind seeing in your pack. Above-average commons, solid uncommons, and decent rares all go here, with all the cards here pulling you into a particular color or strategy (though with less raw power than the above categories).
Lastly, we have the cards that are acceptable to take early but don't make you feel like you got there. These are the bread and butter of Limited and are reasonable signals to see in the first couple picks.
Hopefully this gives you a start as we dive into a new Limited format. Ixalan looks like a ton of fun, and I'm looking forward to exploring it.