Thumb comments would allow for dank memes, which are essential to any forum. I'm appalled that having to click twice would discourage 40% of posters from thumbing. I imagine the only way to bypass that would be to have a textbox pops up when a poster hovers over the thumb button, so that they can thumb with one click or provide a comment also with one click; seems doable, but I've no knowledge of web design.
I would agree with that. As it is though, that is unlikely to happen.