RE: "We need good content" But who defines what's good enough?

You're right, good taste is subjective and strictly relates to the individual expressing it. Used in the same context as Steemit quality content I think there is a line that can be drawn, from a majority point of view, to what is quality/non-quality without too much expertise behind the curtain :)
Upvote herding will happen on quality content. Again quality can be considered subjective, as you've pointed out above, but the majority of whales/users will pretty much have it in the same scope I think (content informative level, originality, catchy titles, good language control, formatting, visuals etc.).

PS. I always appreciate feedback @fishborne, never see it as aggressive unless..you know, it's aggressive (is aggressiveness subjective too? hahah).