This card is interesting, however a dragon creature having a cost equal to its atk|def stats should be a creature and not an creature IMO. Just compare the stats and costs of Golden Dragon/Light Dragon and Azure Dragon/Sky Dragon and you will see what I mean.
Pardon me, but I don't see a relation between this card and your argument. Abomination is another creature with cost equal to it's attack and defense - it seems like Spirit Wyvern could also be due to equal stats (being a 'dragon' doesn't hold much weight given that this isn't an actual dragon and that every element already has one). In fact, putting this in Light would probably be much more redundant than Air because the two cards would be near-identical in stats and cost, with one just having an ability in the hand instead. It's lower-cost ability is meant to make it the mid-large hitter of Air (similar to GoTP/Seraph), which also conflicts with Archangel. The closest thing Air has to a midhitter is Wyrm, which is more mid-small (like Pegasus or Cockatrice).
What I try to say is that in cards with HIGH attack stats and HIGH cost (and NOT the average attack and cost of the Abomination) only
has atk=hp. We're not talking about 3|3, 4|4 or 5|5 creatures here, but for 10|10, 11|11 or 12|12 creatures. The fact it is not truly a dragon doesn't mean something, the discussion is about its stats. You cannot put a high attack & high health creature in an element without comparing its atk,hp and cost with another creature of the same element. Just compare your 11
cost 11|11 stats (or 10
cost 10|10 stats) Essence Wyrm with the 10
cost 9|6 stats Azure Dragon (or 12
cost 13|7 stats Sky Dragon). Your Essence Wyrm is OP in comparison with Azure/Sky Dragon and it would make the dragon of the sky element relatively weak and quite useless.