For Special:MovePage, when preparing to perform a move operations on a page, editors with the ability to "move subpages" can also select "move subpages of talk page" or "Move subpages (up to 100), if applicable". Whereas the list of subject subpages are displayed by default, the list of talk subpages are not displayed, so there is no way to know what you will be moving from this dialog - or if the page count is higher than the limit.
Adding a "Subpages of talk page" display such as the one seen when moving other namespace pages with sub pages would be useful.
Example of a project page with subpages list:
Example of the lack of listing subpages for talk pages that could be targeted by the action: