I added the exclamation point 'cause "nice" by itself is SO damning with faint praise... ;-)
Well, it's a taste thing among others, but I tend to be more grabbed by new ways of saying things and/ or exceptional imagery. My preference in poems is no unnecessary words. So,
A spaniel's ear
is a fractal
in the wind.
Good! Suggestive without spelling things out.
Pedestrian. The words aren't particularly interesting, they don't contribute too much. Just kinda there.
with measure mine-yoot,
in chestnut shades,
"mine-yoot" is cute, certainly interesting, but does it distract or contribute to the poem overall? "curls in chestnut shades", no no no. Is this a beauty feature?
Again, just telling, not the ultimate word choice ever, not particularly evocative, not particularly mellifulous (is that a word? i don't think so but I'm in a rush), not particularly anything. Blonde, mahogany. OK.
flapping in the breeze
like tongues on fire
Better, but I'm allergic to "like" in poems. Just say "ears flapping/ tongues on fire" or something.
much to the animal's distress,
The flapping ears? Not clear.
to the sole.
Cuteness again. Which is fine, I like cute poems too, cute poems have their place. But just expanding on what I said about the promise of the title.