Currently when an issue is voted on the history of who voted on what issue is not viewable via the UI. It would be nice if it were for two reasons:
1) it would allow a manual process of getting approval for sizing defects/new features/etc. by giving managers the ability to simply 'vote' for a feature - when enough votes were collected by approved people the 'new feature' issue could be transitioned to the development group to work on.
2) It is concievable that a list of 'approvers' could be created for the issue and when each 'approver' voted on the issue the issue could be automatically transitioned into a new state or some other action could be taken.

These thoughts are all when looking to implement JIRA in a controlled (i.e. internal) environment. There are several ways to meet this need via existing (though manual) efforts. Several of my users siezed on the idea of 'voting' an issue into production and liked it.

-wc