There's a lot in this, so it's taken me a while to have enough time to properly respond.

I think my style has changed a little bit in the last couple of years, actually. I can usually pick out older ones looking at them. But the major difference over the past two or three years hasn't been as much the appearance as it has the speed: I've gotten better at doing the same thing faster, which has allowed me to try some pictures I otherwise wouldn't have attempted, such as this next one I'm working on or this one I swear I'll complete eventually. But for individual character portraits like this, the difference in speed doesn't really show; the fact that I did this in two days instead of two weeks doesn't really change the result that you see.

Yah, sadly, you're right that the base of the legs are in the wrong position. That redline was what I intended, but not what I drew, even as far back as the original rough skeleton. Just totally flubbed that part, but happily you're the only person who's noticed.

I thought the eye position, head position, hand, and breast position looked okay when I drew it. I'm not sure I see a significant problem in those, even looking at the redline. (The hand may be a tiny bit too big, but I'm going to chalk up its extra apparent length to the gloves.) I think you're definitely right that her right arm is too long, though.

And for the record, I hate drawing hands. Getting the shapes and proportions right is incredibly difficult, especially if you want long, lithe fingers. Hers turned out tolerable, and I'm at least happy that I don't completely cringe looking at it.

As for stylized vs. realistic, I've debated that back and forth for years, and not just for driders. I have a few drider drawings where I went more realistic, and I didn't finish them because they really don't look that good, especially in the legs. In the pictures you've seen, I've generally been going for three-segment legs with the shapes stylized after the shapes of human fingers, curving in, then in, then out on each successive segment; they end up looking appropriate on a drider without looking like actual spider legs. But maybe in a future drawing, I'll give real spider legs and thorax and abdomen a try and see if it still look as bad as the last time I tried it.

The light source in this is a little hard to tell because it's very close to her and fairly bright. If you imagine a single very bright light source about three feet in front of her, about four feet up, and slightly off-center to the left (to her right, about as far over as her shoulder), that's about where I was placing it when I shaded her, and the shadows should match that. As it's a very bright light, it washes out a lot of the color in her skin, leaving her a bit pale and shiny. That was the goal, anyway.

I've experimented with other types of shading, and you can see an example of smoother shading in the silk clothes the sorceress is wearing in my next drawing, as well as on the sorceress's tail. It takes a lot of time to do shading like that, but you're right that it comes out nicer. I've debated using paint tools to try to do shading, but every time I try, I get irritated with it and go back to vector-art-based cel shading, which just feels more comfortable. But I'll make a note to try more gradient meshes in the future; if people really prefer the soft shading, I can find ways to do it without giving up my preferred toolset.

And, for what it's worth, I recognize that you're trying not to be rude. Your comment was intended to be good, constructive criticism, and it's not often you get that on deviantART. (And it was a little depressing, but I can't argue that you're right in a lot of your criticisms, either.) So thank you for your thoughts, and I'll do my best to take them to heart in future drawings.

Neither. It just came together well, and you apparently like it more than some I've drawn. If you compare it to the drawing "Safety", for example, you'll find a lot of elements in common, and I drew that naga girl a couple of years ago. Maybe you just have a thing for spider dominatrixes?