I think tracing is a tool of art like any other. For certain styles it's helpful, it's also helpful as a learning process (it's pretty much how I learned to draw).
However, a tool, if relied on solely, becomes a crutch. Greg Land isn't a bad artist because he uses a lightbox (and he does - some people who used to work with him told me so), but because he's so bad with it.
A lightbox is a wonderful thing. I know professional artists who use it for things like likenesses. When you're drawing a well-known celebrity like Harrison Ford, using a lightbox to get their features makes sense - it keeps them consistent and looking like the person its meant to and thus doesn't intrude on the story. I think many people would like it if the current Buffy artist did this as his faces sometimes are unrecognizable or too inconsistent and it hurts the story.
Other people use lightboxes to compose various sketches they've done into a finished picture (though, this is from start to finish their original work).
Lightboxing is just like photo-referencing. What, you can copy the composition of a photographer's work to your heart's content so long as you don't use a lightbox? Nonsense.
It's about what you do with the references and tools you use. Greg Land is just unoriginal, inconsistent, and lazy in his artwork. It has nothing to do with his lightboxing. Before he lightboxed he was unheard of precisely because he was unoriginal, inconsistent, and lazy in his artwork.
The problem is that now, he's being credited as someone who's really good. If he wasn't tracing, if his work was as it was, and people said he was good, people would just scream he's bad anyway.
Scott McCloud says there are 6 steps to any creative process. The 6th is surface. A lot of people think it's the only one, and if art were an apple and you were to bite into such an artwork, it would be hollow. Greg Land, on the surface looks GREAT. But it becomes apparent the more you look into it, that it is a hollow work. It's just not very good. It's all style, no substance. But that's because he's Greg Land, not because he used a lightbox.
Lightboxes are useful tools for all kinds of draftsmanship.
