This deck exists in spite of every player that thinks that white is mandatory for modern burn. The obvious difference is the lack of Boros Charm and Wild Nacatl. Boros Charm is a fantastic card, but the fact that Bump in the Night is a one cost allows us to run some Skullcracks along with our Atarka's Commmands without ruining the mana curve. Wild Nacatl isn't a card I'd run even if I was running white; it's too slow and does us unnecessary damage, which brings us to our next point: jund burn's speed. The best aspect of jund burn is its speed; having eighteen bolts is where we want to be, and you simply can't have that in naya burn. Let's set up a hypothetical hand consisting of two lands, one creature, and four one cost three damage spells (which is very common in jund burn unlike naya burn). We play a land and play either Goblin Guide or Monastery Swiftspear, swing for one or two and then pass; next turn we play a land, cast two one cost three damage spells and swing for either three or two, and then pass; next turn we do the same. In one of these situations we did eighteen damage by turn three and the other we did nineteen damage by turn three as opposed to naya burn's sixteen damage.
Jund
2+8+8/1+9+9 (bump)
Naya
2+6+8/1+6+9 (charm)
Now of course naya still has a card in hand and will all around do more damage, but in a straightforward deck like burn, isn't speed more important than card advantage? Naya burn's damage per card is better but jund's damage per mana is better. I always like to take the position of aggro deck when playing burn, so the latter is my preference.
The sideboard also changes drastically. White may have some of the best modern sideboard options, but none of them (staples that is) are commonly played in naya or mardu lists for fear of losing consistency and focus, so not much is being lost there. The only card that I would like to use is Deflecting Palm, but Self-Inflited Wound is fantastic in my personal meta anyways, so that's a fine replacement.
