However, in opposition to my own idea, I consider that simply requiring a more effort wouldn't necessarily change the groupthink problem, but would just stifle low effort downvotes.
Let's consider then the whole idea of votes in the first place. Are downvotes considered "speech" in an abstract sense? Should they be protected in the same way disagreeable opinions are? Is the level of effort necessary to express the speech relevant to the level of protection it deserves? Would restricting downvotes in any way be considered a speech restriction?
So these are all interesting aspects to the problem that cause me a lot of internal debate.