The closest you can probably get to this is by setting the default formatting in the left Data pane.
You can select (ctrl- or sift- click) multiple measures, then right-click > Default Properties > Number format > ...
Without mucking about the .twb xml, you can't, for example, change the font on all worksheets. (Tableau does have a copy formatting, but I've never really figured out how to use this.) Ideally, when you create workbook, you setup a worksheet with your formatting and then duplicate the worksheet for sheets where you want the same formatting.
You can also paste default worksheets / dashboards from a "template workbook" to you new viz. ...
I especially like your tip that we can select multiple measures and thus limit click injuries
I also like your info about what is not possible.
Thanks for the screen shot!
Thanks but i have noticed that this is still not working for dates. There is no change when i do the same for a custom or pre-defined format
I want to implement a standardized system for all users