Having different versions of Dragonborn and Goliaths is something. It's going to confuse some ("Which is the 'right' one?"). I can see many DMs banning one version in favor of the other (probably the older version gets banned because "the new one supersedes it"). It's just not a solid choice—if you want the species in the PHB, just reprint the old ones.
That said, the new "Rune Knight, the Species" Goliath is certainly more flavorful than the old "Vin Diesel, the Species". I'm still not sold on it, though.
Ardlings... Can die in a fire. As a posted elsewhere, either put the existing celestial species (the Aasimar) in the PHB or make the new species a non-celestial anthropomorphic animal species and do something with it that's doesn't make it step on the toes of existing anthropomorphic animal species (like the tabaxi, kenku, loxodon, etc.). Personally, I'd just take the hengeyokai (from 1e-4e), call it something that's not culturally coded, and be done with it. It scratches the anthropomorphic animal itch, has a solid theme that doesn't step on the toes of existing species, and is miles more interesting than this Ardling compost.
The Cleric is good. I have few issues with the Cleric. My biggest issues is that the 7th-level Blessed Strike feature steps on the toes of the Paladin. Between that and the Smite spells being on the Divine spell list, the Paladin is being eroded. Thirdly, while I love the Holy Order feature, I do not like Clerics getting a second one. It diminishes the specialization aspect and, with only three available, it's going to cause different Cleric characters to overlap and feel samey. It this stays (and I hope it doesn't), I hope that they make a total of at least five different Holy Orders so that there's more variability in Cleric characters.