Just an idea regarding the lottery - wouldn't it be better to make the lottery daily, not weekly? I think, this way you could convince and attract more users.
Not everybody has time to check it weekly and even for admin it would take a lot of time to monitor it. Having it once a week is better, so it's something you can look forward to.
So please don't change it... my humble opinion.
I second this opinion. If a daily lottery is introduced, it would be best to make this an optional lottery for active users of the site, as opposed to having that become the default lottery. I prefer the weekly lottery, as well.