For me, it's two fold.
1) I feel like I'm never going to be the winner. I'm doing this in my free time, and I don't have as much free time as other people who frequent these forums do. This means that the quality and output of the top level contributors based on previous submissions will utterly crush mine.
2) I've got a lot of work to do, and a family to spend time with, so as much as I'd LOVE to have a shot at a really decent GPU. I hold the value of time with my family in much higher regard.
I felt it was pretty clear from the get go, that theme wasn't required, just appreciated. Maybe I'll somehow get some time, but I think the post production limitations also kind of hindered me because the thing I do of any interest is animation, and I want to be able to do particles and multiple layer comping etc... in it.
Maybe offer 4 prizes of high level value, and the rest smaller level, and set different categories like this:
Octane-components (components incorporated into a final)
Divisions of entries could be in various ways, either setting higher level prizes for experts and lower level for novice so that the really good are inspired to try for the best, while those that don't feel as confident could simply enter a less demanding process. Could just simply be judges saying, this classifies as expert work and this does not (that might be a bit subjective).
This would have inspired me to be doing entries even if they may not be things that took hours and hours to create from scratch and render.
CPU - i7-950 3.06 Ghz, 24GB Ram, Win7 x64, 2 display monitors, GeForce GTX 580 3GB Classified. I'm glad to say I LOVE OCTANE!