@Olivier5,
Agreed. Pop over to Reddit for a few and you'll find their upvote/downvote system is a point of contention in any thread where the slightest of opinions could be expressed on a topic.
I said my piece about the thumbs being a problem for a site that fancies itself an "inclusive community" a few years ago, and was summarily shut down on the basis that the thumbs serve as a function beyond whether or not somebody likes a post/member or not. I left it at that, but it's really kind of a copout, as though there were no other way to implement a "hide post" feature. To this day, I still don't fully understand the function of the thumbs, and a search indicates that I'm hardly alone there, but it's evident to me that the concept is poor design.
But even if the function of hiding topics was properly separated from the thumbs, obviously there could still be the abuse being discussed here. And even if the down thumb were eliminated completely, I'm sure bots could be written to just upvote certain posts. There are many forums that have a "thanks" or "like" option, where the username is attached to said thanks or like, and this would to me be as good a way as any if the powers that be wished to maintain the common tip-of-the-hat feature. Of course, I'm also not clear on whether or not the authors of a2k intend any future development..