I think "impact" as a verb tends to be lazy (and aggravates "our sad want of signs for shades and degrees" to quote Henry James's lament [!]) -- "affect" (which is fine with me), "derail," "disturb," all depending on context.

Refute for rebut is awful in our political and critical discourse. When a newspaper tells me that Romney has refuted a charge made by Obama, and he hasn't, well that's a serious derogation of duty towards clarity and truth.