I find myself using the @acronym@ tag from textile/redcloth a lot lately, and I think it would be worth styling them somewhat so that users can spot them easily. I have added the classical dotted unterline / help cursor to my installation (snippet below), but I'm not sure if it fits the rest of the Redmine UI that well, maybe just having an icon in front of acronyms, like external links have, would be enough.

acronym  {
  border-bottom: 1px dotted;
  cursor: help;
}