Robert Maxwell wrote:
Odo has a few disadvantages: for one thing, he's young. Although this was no impediment to Laas, it seems like Laas was never under the thumb of a solid. Odo, on the other hand, was pretty much at the mercy of Dr. Mora and the Cardassians for much of his life. Odds are he didn't get to explore his abilities a whole lot under their gentle tutelage. He also hadn't had a lot of exposure to his own kind.
I agree with this. Plus, IIRC, Laas first started shapeshifting over a century earlier, whereas Odo started taking on non-gelatinous forms little more than a decade before the series started. So Laas has had a lot more time to practice. Odo is still maturing as a Changeling.