You're suggesting that the whole thing Kato did with Elements could have been done using Zeal as the basis instead of the Reptites. That I can understand. But your idea still isn't fleshed out.
I've haven't "fleshed" it out in direct response to your post, but I have posted regarding this back on November 13th, 2008. Effectively, spekkio says that the 4 elements comprise all matter in the effective universe, and innate magic is the manipulation of these forces. Additional quotes and compendium articles place shadow as at least being in effect a combination of the other 2 to 3 elements. So in effect, a sufficiently skilled shadow magic user, could manipulate all effective matter. If he's capable of manipulation of all matter (and from a physical sciences perspective, all these 'forces' are also matter being manipulated) than any effective ability combining the "dragonian" elements together, could essentially be done as well by shadow magic manipulation. Thus, one aspect to not needed CC elements for the effective story.
Additionally, I'm going to broaden your question and respond by saying "both" again. Either using the effective CT system (as above) can work, or again, using the current game history to effectively "create" draconian elements in CT still works too. For one, any manipulation of matter for force (no matter how magical) is still a manipulation of matter (as again, I stated in physical sciences, "magic" is simply specific manipulations of matter) and the draconian method is simply a development of technology that allows for said manipulations of matter, which in effect, doesn't matter on the person, but strictly on the tech since any character can pretty much use any element. The nature of how this tech works had no given limiting factor that can't have such tech be developed through human evolution, as they've already demonstrated a knack for having tech that can at least emulate some magical effects (like The Zeal lazers) which, frankly, I don't see as too different from CC since in CC you buy individual spells to socket to the characters grid.
Furthermore, you're quoted line from the retranslation "Zeal has prospered this much through the use of a new energy far more powerful than the planet's powers of sky, dark, fire, and water." is actually a further demonstrator of my point because it directly sites the planet's powers, powers you said are "Planet-centered way of the Reptites/Dragonians". Such a claim, that directly sites the planet's own innate forces of fire, water, sky and dark still points at the elements of CC. Why? Because it is the "planet's powers" of said forces. Those 4 comprise the effective matter of ALL the universe, not just the planet's own; which then makes sense why Lavos' energy, which is effecting ALL, would be superior to the planet's own. As I see it, semantics aside, either CT only features manipulation of only some of the planet's forces (and the dragonians figured out how to use the rest) or its just a difference of game mechanics now; one used 4 for simplicity, the other uses more because it wants more variety and has the memory capacity to handle that.
The key point here being, that in order to make a comparison of Lavos' powers to that of the elements still requires Zeal to have a grasp of the effective power of the planet (ie the CC elements) Thus, in my eyes, my idea still stands.
Furthermore, you're still not taking CC our of the equation in your thought process to see mine. For one, you not only reference the Frozen Flame, something that didn't exist in CT, yet accept because CC said it was there; which, oddly enough, when you read into that and older forum discussions, creates another story plot hole in how the chosen of the frozen flame works out in effect between Schala and Queen Zeal and Serge.
I digress, but point being, you've accepted and take a factor not in one game for granted because the most recent game said so. My point being, that another game could simply do the same thing again.
Something like "Oh, Zeal was made to float because the palaces had underground generators that could manipulate the elements because human kind made devices to manipulate the elements before the Frozen Flame was utilized in the Mammon Machine" And wow, something that is almost completely overlooked in an older game becomes a potential plot development point in other. It's not like I need to magically edit Trigger to create some auspicious plot point for a game sequel.
Now, to further differentiate our viewpoints here, I'm going to address the point about Lavos and magic. One of the additional factors I find in CC being bunk is this notion that humans needed the Frozen Flame, or their interaction with it, allowed for magic. Okay, so what about the Mystic's? They didn't contact the flame indicating that "Magic" as we know it in CT is not directly dependent on that Frozen Flame. If that's not a direct factor there, than the possibility for human's to evolve innate magical use in some given time line/dimension is a possibility; just as the reptites evolving into dragons is a possibility. So, then, humans could then develop "elemental tech", and, again, I say, it could make a lot more sense to bring that out then the megalomania of the Chronopolis plan.