My posts are typically shorter than longer, and I would say it depends on the subject your are writing about.

Long opinionated posts deserve to be as long as they want. The writer needs to have freedom to explain their whole point of view, and allow the reader to get the whole story.

On the other hand, posting a pic and a short explanation about it warrants a few paragraphs. No need for a long drawn out post. Same goes for posts with videos. The video will tell the story.

I think both approaches can be successful if the content is well written.

Good luck with your strategy, and thanks for sharing.