No matter edition or system, any RPG designer who generalizes eeeeevil as ugly won't have my support.
People really have different opinions concerning art, I dislike most of the images, in special the cartoon style for creatures that should inspire fear, not laughing.
Wotc is thinking it pleases an younger aundience.
I have serious doubts about it.
I understand where you are coming from, equating evil with physical ugliness is not fair way to look at life. But, it's nothing unique to this new D&D book, or even to D&D in general. Human mythology and religion worldwide has a long-standing tradition of equating spiritual ugliness with physical ugliness. In fact, the beautifully evil fey stand out as truly insidious because they buck this trend!
Quick! Name the "evil races" of standard D&D fantasy. Your top 5 (heck, your top 10) are probably ugly suckers. Orcs, gobs, gnolls, gith, flayers . . .
Now quick name the top 5 "good races" and they'll all be sexy in one way or another! Elves, dwarves (ruggedly handsome), halflings (cute), gnomes (even cuter).
Now of course you'll find evil individuals amongst the so-called goodly races and the Klingon Effect has changed our viewpoints somewhat on some of the uglies (shamanistic, nature-loving orcs). But these are exceptions to the rule.
If anything, D&D 4e has taken some slight steps away from this long tradition with the more wierd player races such as dragonborn, genasi, shifters, the new deva, etc.