Roth UI (Diablo)
How to only increase the actionbars + bottom bar panel?
If you only want to increase the size of the actionbars and the bottom bar panel including the orbs you can do so.

1) Open oUF_Diablo/config.lua and scroll down to the player settings.
Increase the scale of the player from 0.82 to 1.

2) Open rActionBarStyler/config.lua and change the scale of bar1, bar2 and bar3 from 0.82 to 1.

Save the files and do a /reload in the game.

Obviously 1 is just a number you can use any number you want.