Currently Jira doesn't allow you to graphically move issues between swimlanes, because it's said that it can't really tell what modifications are needed for an issue to meet a certain criteria for a swimlane, basically because they can be complex.
However, many times the conditions are not compex at all and they are based just on a one field filter. For example, if you have a swimlane for "priority = High" and other for "priority = Low", Jira could easily consider the lane as "switchable", because the only thing that it would need to do is to set the priority to Low or High depending on the swimlane. It could even detect ANDed conditions, like "priority = Low and assignee = Peter". Its obvious that for an issue to be there it has to meet both conditions, and it's obvious for Jira what to do (set priority to Low and assignee to Peter).
Different are the cases where conditions are ORed or lists of values are used, but for many, many of the cases, this could be achieved quite easily.