I believe the problem with the down voting button is it often reflect more on the opinion of the voter rather than how well the article was written or its usefulness.

Good article that agree with the user = comment/up vote

Bad article that agree with the user = ignore

Good article that disagree with user = comment/down vote

Bad article that disagree with the user = down vote

Unless everyone actually vote up/down purely base on how good the article is and not their opinion, removing the down vote button is not a bad idea...

The voting button is a good idea if it's a poll, but the "hotness" of something is probably better tracked by the comments and other actions a user take...