"Heart of Kiran: Planeswalker Powered things begin."
Virgilio F. De leon Jr. MD
At first glance the Heart of Kiran looks like an early attacker. It costs just 2 colorless mana like the Smuggler's Copter and it seems like a desirable addition in Aggro decks since it is a 4/4 Flying ,Vigilance creature when it is crewed but on closer inspection it is really much slower in Standard because of it's 3 Crew cost and there are no 1 drop 3 powered creatures at the moment. It is at least viable on turn 3. Where you could attack with it with a Veteran Motorist , Depala or Foundry Inspector Crewing it or if you have Saheeli Rai in play. Simply remove a planeswalker Loyalty counter from Saheeli and you don't even need to tap a creature to crew it.
It seems that Wizards of the cost R&D would be developing new ways in utilizing planeswalker loyalty counters(PLC) and it won't be long before we start spells cast in this manner or other abilities requiring the PLC as an alternate cost which is exciting since it is another avenue of development for our much beloved game. Planeswalkers actually powering creatures and spells. Exciting times.
Sorry about that I tend to go on tangents when I am excited about something. Back to the Heart of Kiran , being a Legendary artifact-Vehicle it will be limited to 2 or 3 copies in a deck since it would really suck to have two on your opening hand as opposed to having 2 Smuggler's copters in it's place. Having to draw it much later on because of it's scarcity in a deck is good because it would shine better in the mid to late game anyway. Probably after you have a Chandra , Fire of Kaladesh in play to power her father's legacy to aid you for a win.