While working with issue, it may be useful to ask for review in a kind of 'for your information' manner, meaning you don't want to reassign the ticket.

It would be nice to have 'Ask Review' or 'Notify' action where you specify a person (ajaxed field) and some message like 'Take a look at my current solution and let me know if any concerns' and then click Send. As a result email is sent to the person containing back link to the issue, name of message author and message itself.

This way ticket is still being assigned to you and continue working on it, but you send some personal email to your colleague/manager about it. Such message is easier to distinguish from lots of notification coming to you as from other jira workflow operations.