My main concern at the moment is I still don't have a good feel for what I want my secret themes to be like. At the moment my competition doesn't have any big restrictions like the one button rules for 1W1B, the three hour hard limit on capn_midnight's comps or a code from scratch rule that many comps have. I'll need a slightly more restrictive set of themes for it to work; I can't just go with something like "collecting" as many people will have existing games that do exactly that.
The problem with a more restrictive theme is there's a big danger I'll alienate people if they don't get a theme they like. For example, I'm strongly considering going with two random themes, one for gameplay and one for the presentation, setting and aesthetics. However if I end up with a presentation theme like "Baroque", I expecct many GameDevvers will think "WTF?" and not want to join in. But likewise I can't pick the same typical cliches that everyone uses in their games as potential themes, as chances are people will have a demo game that does exactly that.
Despite the initial opposition to it I may still yet resurrect my "no violence" rule - especially if I pair that up with secret themes that would ordinarily suggest violence (pirates/ninjas etc.). I know there was objection to the no violence rule, but honestly there's meant to be some kind of game design challenge in there and if people can't think of a good game idea that involves, for example, pirates and no violence then they've not got a lot of imagination.
I'll need to put some harder limits in there to make things more interesting but I'll see what people think in response to the shaping competition. Hopefully I'll have a brain wave sometime this week for how this thing should be run, otherwise I'll just go with whatever seems best at the time.