I think the subject matter of a post is much more important than it's length. A well written 300 word post can convey the same message as a poorly written 1000 word post.
Agreed. I don't go around looking for posts that are a certain length and upvote them accordingly. In fact, I'd be willing to bet that most users wouldn't even consider that as a factor in determining whether to upvote or not. The average user votes on posts that they like - the rest of the users vote on posts that they think will earn them the most curation rewards. The length of the post has nothing to do with it. If voting is skewed to a certain type of content, then there's likely one of two reasons for that.
The average voter has generally decided that a certain type of content is more valuable than another.
Those with the most influence have created popularity for a certain type of content and other users have adapted their voting habits to cash in on the expected rewards.
In the case of number 1, isn't that exactly how the platform is supposed to operate? In the case of number 2, the best solution is not to create another group of influential voters to vote for the other content. The best solution would be for the influential voters to become better curators - and maybe stop automating their votes and creating/joining large bot trails.