I think the number 1 thing is facial recognition. Having your face on the thumbnail for the DTube curator(s) to recognise I think is the most important thing. "Quality" has almost nothing to do with it.
Having said that, quality is subjective - so what is good to you may not be considered good by others (DTube). This subjective bias unfortunately curates the DTube platform to a few people's taste.
That's true man, you bring up a lot of good points! And that's kind of why the whale issue right now makes the upvoting process not decentralized.