I thought Jeph did Dora really well in the last comic, except, admittedly, in the last panel.
Honestly, his problem with her is pretty simple. I don't know why, but he can't seem to figure out how to locate her features in her face, and also that she has a narrow face, not a round or square one. He seems to do better with broad-faced female characters (like Faye and Marigold). Dora's face, especially when drawn full-on, needs to TAPER from just below her eyes to her chin. A girl will look swollen and unattractive if her lower face is rounder than her upper face, which is kinda what keeps happening with Dora. Also, people with longer, narrower faces don't look good with a mouth too close to the chin. Dora looks good in all the other panels because her face is tapered properly and her mouth is slightly higher up. Jeph also for some reason makes Dora's nose really bulbous in profile when in fact it's sharp and pointy.
To sum up: when drawing her face-on, she needs a narrower face, a narrower nose, and her features better balanced in said face. See?
It doesn't look quite right still because I feel the mouth remains somehow off, but it's better. (Whoever said her mouth is drawn too big is right, I feel--again, it would work on a character with a wider face, but not with Dora.) I've done this on another picture of Dora before.
(here I just narrowed down the face and did nothing else.)