Would like the option to arrange worksheets vertically too (maybe up to 3 rows of tabs). Makes it easier when files have many worksheets.
Also, in older versions there were arrows that would let you scroll through worksheets and another set of arrows that would go to the beginning or end. The latter set of arrows is gone in the new version. I do not like that feature having been removed.
I'm also for this idea. Having multilayered tabs would make navigation much smoother and allow for quicker access between sheets.
Have you tried right clicking on the arrows? Not exactly what you're looking for, but perhaps an acceptable workaround for you...