I find that when I am reading a question or an answer ( especially a long one like this), I will often just upvote/downvote it even before I have finished reading! Call me lazy, call me whatever you will, but sometimes scrolling down and up to finish reading and only then vote is just cumbersome. So I resort to my intuition: when I see a upvote/downvote button, my impulse is to glance at the text and judge whether the question/answer deserves my upvote/downvote and then vote immediately, without bothering to read the whole thing.
Putting the upvote/downvote button at the end of the text will reduce the temptation to jump to conclusion, and result in a more thoughtful vote. So it would be a good UX change. What do you think?