Oh man. I just lost a whole long post.
I don't have time to say everything over again, so I'll try to be brief:
Child, Lewis may have had beautiful, female villians, but I recall beautiful female heroines, too - Psyche in Till We Have Faces and Ramendu's Daughter in The Voyage of the Dawn Treader. Also, Lucy is not described as ugly, or not pretty. She's a normal girl. However, Lucy, out of all of her siblings had the most faith in Aslan. If Lewis were sexist (a fierce glance in Lal's direction) why would he have made his most faithrul, upright character a girl in Narnia?
I was going to correct Gwathagor's mistake, but I see you already have.
I would like to make an illustration...of what Lewis meant with his 'handling' of Susan.
When I was younger, Lucy's age in The Lion, the Witch, and the Wardrobe, I played with qutie a few girls. We ran around outside in the woods and field and played and pretended and did all sorts of fun stuff like that.
And then a time came when I didn't see some of these girls for a while...about four or five years, probably. When I saw some of them again at a wedding shower, the first thing I noticed was how much they had changed, and the second how little I knew them. I had not changed much...I was still playing in the woods, getting dirty, and playing out silly little pretend stories...at the wedding shower, I wore no make-up and I had on a simple, modest cotton dress. In comparison, these girls were wearing make-up (painted to perfection), tight jeans or tight, short skirts with nylons (I don't think that's how it's spelled), and snazy shirts. The gap, which had been so narrow before, was chasm wide between me and those girls now - and mostly because of the way they dressed and spoke. Their ideals had left the simple, down to earth character - the type that could let them play out in the woods and play - and flown upwards to catch the attention of the boys and society.
That's what happened to me, and I think that Lewis was making Susan into one of those girls that I used to know. He wasn't punishing her...nor was Aslan. Susan was punishing herself.