Well, thank you for expanding the definition of proof the brain. I always thought it means that an article or a post is a proof of brain while it means a whole lot more than that. Everything that we do is proof of brain including posting photo, upvoting, commenting, building application, playing a game, drawing a picture or doing exercise. This makes more sense.

The long article vs short article is a very interesting subject. I have an impression that long article is preferred on steem. For example, a tribe or a dapp state that if we want to post an article to them, it has to be minimum 250 words or something like that. Less than that is consider not meeting the quality. Recently I tried to write longer article with more details and photos hoping to get higher reward.

I also see short articles or photos (not Beyonce wearing steem T-shirt) have higher payment than a long article with elaborate explanation and great photos. Well, It's not something that can be predicted. Long article and short article both have chance to earn reward. LIke you said, let the new steem does what it does until it crytalize into something definitive, CMIIW. And steem is not just long post or short post, it is everything proof of brain.