There are two conflicting forces that work on your mulligan decisions in Ixalan Limited.
On the one hand, the format is quite fast and punishing. If you’re on the draw with no play until turn 3, you may be dead before you feel like you even got to play. Similarly, it feels bad to keep a hand that’s vulnerable to the opponent suiting up their creature with One with the Wind or Pirate’s Cutlass.
On the other hand, there’s very little card advantage. There’s pressure to assemble tribal synergies, and the cards tend to have an individually lower impact in Ixalan than in some recent Draft formats. It can be difficult to recover from a resource disadvantage.
Balancing these two concepts is key to making the best of a bad situation.
Hand #1: Booster Draft on the Play
I’m not dead-set against keeping hands with only one color of mana, but this hand will not be functional until you find a Swamp. Also, this is a hand that wants to curve out and force the action, not one that will play well from behind if you hit your Swamp on turn 4. Replace one of the creatures with a Fathom Fleet Firebrand and you have my attention, but I’m not happy with this one as it stands.
Hand #2: Booster Draft on the Draw
Starting with five lands is not ideal, but neither is going down to six cards. You’d breath a sigh of relief if you saw four lands in your mulligan hand, but that would leave you with two spells anyway, so why risk mulliganing to oblivion? I like to keep five lands with two good spells, but mulligan five lands with two clunky or mediocre spells. Deathgorge Scavenger and Pious Interdiction count as “good spells,” since you can cast them in a reasonable time frame and they can help you survive long enough to draw out of an awkward start.
Hand #3: Booster Draft on the Draw
This hand has a reasonable mix of lands and spells, and I typically keep two land hands on the draw. The problem with this hand is its inability to play from behind. Your cheapest spell is a trick that requires setup and can’t be cast early. Your first play is likely to be Lookout’s Dispersal on turn 3 on the draw. If your opponent has a good start on the play, you’re going to get buried.
I had this hand and I kept it (somewhat on autopilot) and I lost badly. Afterward, I decided that I needed to re-evaluate my mulligan decisions for Ixalan Limited. It’s crucial to get on the board early, and opening hands full of nonsense combat tricks and no cheap creatures are liable to get you into deep trouble.
Hand #4: Sealed Deck on the Play
This is similar to Hand #1, but three subtle differences impact my answer. First, it’s Sealed Deck instead of Booster Draft, where the games are usually slower and more forgiving, and where raw resource advantage has a stronger ability to decide the game. Second, you have a creature you can play—Territorial Hammerskull—if you find a Plains but not an Island. Third, this seems to be less of a mindless aggro deck, with a little more ability to play from behind.
Hand #5: Sealed Deck on the Draw
This hand already has too many lands, and needs to draw more to be functional. You’re hoping to draw a Swamp right away, but if 3 or 4 of your first handful of draw steps are lands, then you’re going to be hopelessly mana flooded. Combine that with the failure rate of not finding your black mana, and I think you can do better.