Hello Daniel,
at the moment the ist is blocked for a longer time if these "special people" are working on their tasks.
So if you implement the "check out a single task" then these people can be "educated" to check or 2 or 2 tasks at once and then update the comments.
Later they should check in all tasks at once.
One new idea:
When I check out the complete task list (the existing toolbar button) you should show a message informing the user that he also can check out a single task instead.
Maybe you add a "Don't show this message again" checkbox.
Best regards
OLLI