Your community consists of quality content. The quality of the content will increase with the new rules. I don't think there is a word count limit in the rules. There could have been at least a 200 word limit.
You will have a hard time at first because you changed the rules. Because most of them will not notice it unless you warn them.
I say "put in some effort" in regards to work count. If people try to abuse, they will end up more than muted. :)
Yep - so I aim to be actively warning