I said pretty generic rather than just generic for a reason. EARTH is one of the most common attributes, so it's doable in a large number of decks. (Whether it's worth it or not, it's not HARD.)
What kind of weed are you smoking, this 🔥 is garbage.gigancicastle is much better. And flamevell uruquizad has an actually good effect and much more generic than this sunflower lion 🔥
Gaiastrio does not specify "Naturia Leodrake", or even "Leo, Keeper of the Sacred Tree" (which is the direct upgrade form of Leodrake before Gaiastrio).
"Leo, Keeper of the Sacred Tree" doesn't list Leodrake as material either.
In fact, we actually have more chance to get Gaiastrio than Leo Keeper, since Leo Keeper's only effect mentioned MP2, meaning its chance to appear in DL is 0%.