The problem with maximizing a post's length is that it most likely means one of two things. Either you are putting in way too much information and dragging it out so far that it will be hard for others to respond to all of the actions in it, or you put in so much detail you mention the mosquito across the road on your grandmother's windshield.

My issue with super long posts is that after an action in the first couple paragraphs, if you put like six more after that, who's to say that the reaction the action you took in the first couple paragraphs doesn't hinder other actions you took later in the same post? In many cases such as nation RP this is okay as you are mostly typing up what your own nation does or just updates on activity. Most people seem to believe that other players in a RP won't respond until after their post and that their characters are just standing around until then. The truth is response posts will respond to actions you took as they happened, not having their character respond to action 1 after action 9 is done.

I don't see RP as a game though. A game implies there is a goal and a way to win. RP to me is collaborative writing, and it's hard to collaborate when you assume things about your partner's responses.