We don't even have a good specification yet. Even if you add a specific number, "casting too many votes" isn't really what we need.

Ironically, I believe the problem could actually be not enough voting by the regular users. That gives a rabid voter such large fraction of the total votes on the website.

For the record, I would support a software solution, but it would be one that would do data analysis in order to find various kinds of voting abuse (retributive downvoting, sockpuppetry, etc.) and would provide reports to moderators. Clicking the "ban" button is the part that only takes a few seconds. Analysing the data to find out if the user really does what they are accused of, that takes a lot of time, because it's currently done ad-hoc, and because the Reddit code and database are unnecessarily complicated.