Seems everyone wants to put shadows in their movies now. Then again, that's human nature... something gets popular, everyone looks to get their piece of the pie. Take the movie Avatar for example... how many 3D movies came out right after that?
Cowboy X by Nikolas Frederix started the crazy - shadows were used very well in this film. They added to the movie the sex scene and didn't "over shadow" it or were they a distraction.
Other movies followed I really loved the use of shadows by Prince JD in stranded. The shadows during the dancing scene made it that much more of a romantic environment.
Today I messed around with shadows with three different viewers Phoenix - Firestrom and current Phoenix, and Kristens. Honestly, my laptop is limited to what I can do with shadows on, but that wouldn't change my opinion of shadows. While doing this I watched the movie "Due Date" and a couple of other movies previously the last few days... watching exactly how much the use of shadows play in real life movies. All honestly, not a whole lot. Here and there but usually very briefly or very subtle.
Shadows are transparent...they don't look like black paint splattered all over the place. In the end, seems some people think that by adding shadows, it makes their movie better. In some cases shadows can enhance a scene, but it's not make a break.
Myself, I would rather have smooth animations then choppy animations with shadows. To me shadows are the cherry on top of the sundae, but you need the ice cream and topping first! I always tried to shoot my movies like a real hollywood/porn movie. Which is why I could never understand the whole "flying camera" craze. To me that's just someone being lazy. Instead of shooting from different angles and editing them in, they pan from far and try to get all angles in one shot, yet really none of the shots are that great in the end.
When I made my movie "School Daze" my goal was to get as many close up shots as I could, putting the viewer in the action. Sure, it was extra work...especially some of the threesome shots, but overall I think it was well worth it.
So in a sense shadows should add depth... maybe help set up the real reason you are making the film. They shouldn't attempt to be the "star" of the film.
As for Kristens being better for filming. I shot half my movie "School Daze" with Kristens and half with Phoenix. Don't really matter if you have a decent editing program which can enhance, sharpen, color correct the film to your liking. It might be a little more work, but in all reality, a movie is only as good as the time you put into it.