I agree with what rez said, but think red is our weakest color (avalanche tusker remains an indefensible pick, up there with our first pick). Only death frenzy demands a black source to work, and it's probably a sideboard card anyway.
The thrust of his reasoning is good, however, and I'll vote for the bloodfell caves as well.
The real second choice isn't scaldkin, though, but the alpine grizzly. The card plays very well with our combat tricks, letting it beat a morph in combat on turn four and either trample in for a ton or leave behind a 6/4 monster.
This is an easy Efreet weaponmaster. There are a lot of great cards for our deck in this pack, but none compete with the Efreet. It's one of the reasons to be jeskai in the first place.
Hordeling outburst is cool, in that it's a creature and a spell, but it's not a god creature, and it's sorcery speed, so it's less valuable as a prowess trigger than others.
Monastery Flock is better than the windscout in all but the aggressive prowess decks.
That brings us to 13 creatures, and roughly 20 playables total. So we're out of the danger zone, and really just looking for another good card or so, plus upgrades.
It's unlikely we play more than a few red sources in the deck, so summit prowler is uncastable. Weave fate or Kin-Tree Warden are the options, I think, and the creature gets the nod. It's replacing a Canyon lurkers or archer's parapet, which is a nice upgrade.
This is a really tough pick. Throttle will always be good, but Tuskguard captain has some great synergies with our feat of resistance and Armament Corp. Both picks fit our strategy well.
Both at this point are upgrades: the throttle will upgrade a kill shot, and the captain will upgrade a Smoke teller. Out of those two choices, I think the Captain is the pick, but it's very close.
We already have a ton of morphs, and kin-tree isn't that great. I'm more interested in another interactive spell, in this case our second force away. We've got a few ferocious enablers, and it helps fuel our many delve cards. It also gives us more action on turns where we've left our mana up to potentially flip morphs EOT.
Rugged Highlands. The tuskguard captain is my next choice, but we have the typical khans problem of too many three-drops already, and so it would only be an upgrade (albeit a good upgrade, likely replacing the kin-tree warden).
The thrust of his reasoning is good, however, and I'll vote for the bloodfell caves as well.
The real second choice isn't scaldkin, though, but the alpine grizzly. The card plays very well with our combat tricks, letting it beat a morph in combat on turn four and either trample in for a ton or leave behind a 6/4 monster.
Let's pray we see one on the wheel. Without one, this deck is good but not great.
Chief of the Scale is the best of four solid choices.
Hordeling outburst is cool, in that it's a creature and a spell, but it's not a god creature, and it's sorcery speed, so it's less valuable as a prowess trigger than others.
Monastery Flock is better than the windscout in all but the aggressive prowess decks.
That brings us to 13 creatures, and roughly 20 playables total. So we're out of the danger zone, and really just looking for another good card or so, plus upgrades.
Both at this point are upgrades: the throttle will upgrade a kill shot, and the captain will upgrade a Smoke teller. Out of those two choices, I think the Captain is the pick, but it's very close.
We don't need creatures. We have, like, sixteen creatures.