Since the rotation of Thraben Inspector, Toolcraft Exemplar hasn't been nearly as ubiquitous in Standard. Consequently, Heart of Kiran has taken a hit in stock as well. Mardu Vehicles is still around, but in a much more aggressive shell with Hazoret the Fervent, so it's just not the same.
Today's deck returns Heart of Kiran to a midrange shell, choosing to surround it with powerful green and white cards while touching red for some other goodies. The main pairing is certainly with Gideon of the Trials, which crews Heart of Kiran via its second ability quite nicely and does it on-curve to boot. The pairing creates a ton of pressure that by itself can end a game as early as Turn 5, is difficult to block, and can play some defense if necessary.
Second, Heart of Kiran pairs nicely with Glory-Bound Initiate. As an attacker that can sometimes be mitigated by Thopter tokens, having a non-combat use for Initiate is quite helpful, and of course it can still get in as a 4/4 lifelink creature with exert should you need to play both life totals in a tight race.
Chandra, Torch of Defiance and Nissa, Vital Force give you two other planeswalkers that can crew Heart of Kiran, and Rhonas the Indomitable can crew it when you don't have a four-power creature, so the Vehicle goes a long way toward letting you get the most out of your other threats, which happen to be fine cards on their own, so you're not sacrificing much.
Given the power level of these threats, Blossoming Defense makes sense as a cheap card that can fill your curve and gain some tempo against the various removal spells in the format costing two or more, at which point Settle the Wreckage comes in as a powerful removal option in a deck that doesn't have many remaining spots for removal, albeit one that is an awkward fit in the curve.
It's pretty hard to evaluate decks like this on paper, since they really depend on how the individual cards match up against the metagame and there aren't a lot of clear synergies to work toward. But all the cards in the deck are standalone playables in Constructed, and in particular, I think Heart of Kiran is a great card without a solid home right now, so trying to find that home is a good angle on the format. Moreover, the decks that do play Heart of Kiran tend to be underpowered elsewhere, and this deck tries to solve that issue with the possible exception of Prowling Serpopard, which is a classic "good stats, mediocre product" creature, especially when compared to Rogue Refiner.
I do worry about the mana here with so many multicolor lands that will likely enter the battlefield tapped, but opening on an Evolving Wilds goes a long way toward smoothing your draw out and red is a splash color, so it should be workable. We're nearing the end of this Standard format, so it's a good time to break the monotony of Energy and remember the good old days when Gideon was everywhere instead.