Here's some thoughts:

• Suggesting 1 or 2 themes instead of 3 would be a nice idea since going through 2600+ themes is pretty time-consuming, and some of the themes looked like a filler.
• Some people should check spelling before submitting.
• Would be really nice and handy to have some kind of schedule to know when what happens: when the Theme Slaughter ends, when voting 1 starts, when voting 2 starts etc.