There is no option in the game to 'always display extended hold hotbar'

[Brandr]

Although having more options to the game is always good, you already can do what you want with the options the game has now.

You know you can drag skills to 'normal' hotbars (the ones that are not cross-hotbars), right?

And you can macro all hotbars including cross-hotbars to hide and show whenever you want with one press of button.