No, the leader of the Huns in Mulan is the best villain. Hell, all of the huns in there are awesome.
Why?
Remember that scene where his pet hawk returns with a doll from a mountain village? I.E. the one that the chinese army is guarding to prevent the huns from making a straight run through to the emperor?
Yeah, the huns figure that out... just by examining details on this doll.
They are the best disney villains because they are the only ones with more than two brain cells to rub together. Every other villain from Hook to Maleficent to Scar and Jafar are complete idiots. Oh sure, Jafar managed to fool the Sultan for all those years, but that's only because, as the film establishes, the Sultan is a complete moron. Not exactly an impressive feat to trick a moron, is it? As for Scar, yes, he was a bit smarter than Jafar, but no one in the film is bright enough to immediately suspect him of villainy until Simba comes back and exposes him (or rather, threatens to slit his throat if he doesn't talk), and even Simba didn't suspect his Uncle until Scar decided to be an arrogant douche and TELL HIM a few seconds before Simba manages to turn it around on him. Which, again, makes everyone Scar tricked look like an idiot, when it is perfectly obvious to the audience THE ENTIRE TIME, that Scar is the villain. (and that's clear in the first five minutes of the film)
Now, the huns on the other hand, they not only figure out where the bulk of the Chinese army is based on that doll, but they then proceed to storm right into the village the army is guarding, and wipe the floor with them. Which clearly establishes them as a credible threat that is impressive to see Mulan and her allies take down.