controversial posts are likely to get opinion flagged

One of the biggest issues with virtue signaling is that its usually a facade to hide the truth. Forcing people to put their money where their mouth is evaporates most virtue signalers instantly. In an environment where something like steem has mass adoption then opinion flagging will not be nearly as high as you might think.

I really doubt that, outside of a few invincible whales, we will see about the same levels of opinion flagging we see now.