There's different kinds of dragons anatomically, so your preference would be Wyvern-style dragons for the tetrapod part. Six-limbed dragons (four legs, separate wings) are the classical, Western interpretations.
Forgive me if I'm lengthy, but these are just my thoughts on the matter as well as some input there, since I find this comment interesting.
You can never actually be wrong on what's a dragon and what's not when it's still under the lines of being a dragon. Now, I'm not saying someone is right if they think a griffin is a dragon or something, generally speaking something like those are two different, I'm talking about interpretations universally expressed as dragons).
That being said, you can't actually judge or prove whether or not an interpretation of a fictional creature is "correct" or "incorrect," as dragons vary far too much across the board in literature and mythology around the world and throughout time. They are creatures up to the interpreter's imagination, so while a certain kind of dragon may not be "correct" to someone or a group of people doesn't it isn't "correct" to another person or group. It's like if people think that only Western styled dragons are the only actual dragons because they are the burly, powerful winged dragons, that's like telling let's say, Eastern peoples that the Chinese dragon isn't a dragon because that dragon does not fit their cultural/mythological/literature preference aligned to Western dragon interpretation. However, both kinds are indeed still dragons no matter how you look at them because they are all based on cultural and individual preferences.
In reality, there's no real "authority" on dragons, not even Martin or Tolkien, as they themselves expressed their own views and interpretations of dragons; Tolkien's Smaug is usually interpreted as a serpentine but a six limbed dragon from the book as far as I've read and I've known, so saying an interpretation is incorrect is not necessarily viably factual. In fact, many people were a bit shocked that the recent Desolation of Smaug's interpretation of Smaug was four limbed, seen to many people as a wyvern (of course, a wyvern also varies widely in general dragon lore) that caused people to say that putting Smaug as a four-limbed dragon was not accurate to Tolkien's work. This is obviously based on multiple speculations and perceptions, just like your or my opinions and preferences on dragons.
So in the end, it all comes down to personal preferences backed by personal choices of "authority" on dragon interpretations.
Well mostly it's true, and as they are fantasy creatures there is a huge freedom to imagine them as one would like to. And my perspective is mine, some people share it, some has different opinions. What I can tell about my version is that I try to find regular patterns and try to imagine them as "real" as possible, this includes the basic anathomy of real animals. In this case I like more the depictions of 4 limbed with upper limbs evolved into wings (like the prehistoric flying creatures). However hybrids like Chimera or gryphon might be interesting also, as long as they are "properly" built with bones and muscles. For example I find uninteresting eny depictions of such flying creatures whose wings would be too small to lift them, or they visibly don't have muscles and joints attached to those additional pair of limbs.
Well, exactly, it's your perspective; I'm not saying yours is wrong if that's what you're thinking. I acknowledge what you say as your interpretation and I have absolutely no problem with it. There's absolutely nothing wrong with going by what you feel to be a more "right" interpretation of said fantasy creature and finding real ways, biological, etc., to try and explain such. I have nothing against that at all, because I do it myself. Maybe not always with certain things like dragons, since I personally like to vary with them including on the limbs, but you get my drift, hopefully. Biological realism (and realism in general) to some degree helps such become more "real" and interesting.
I'm really responding to your comment on the "incorrect" statement and backing your view with "authorities" like Tolkien and Martin, who are doing no more than what you or me are doing; going by their own interpretations from past lore. Past lore including many "incorrect" interpretations, spanning from old mythologies to medieval lore to even the dragon in the Book of Revelation in the Bible; trust me, those are definitely bizarre and more "incorrect" than you could possibly imagine. You don't have to like them or anyone else's, but they're never actually "wrong," is what I'm really saying.
Mainly, it's better to say that "I don't like this interpretation because I feel this way but that's my view" instead of saying "no, this is wrong because I find this wrong and it's wrong because so and so said so and I share the same viewpoint," because that's simply not true and full of fallacy, that's mainly what I'm getting at.
Pretty much, great big okay for not liking a certain interpretation. Not okay to say it's wrong because it doesn't fit what you like and back up.