I suppose the 10-button toolbar is assumed to be your "Captain Powers", but obviously it doesn't have enough buttons to be useful once you start putting Bridge Officer abilities on hotkeys. This means the default view is pretty much useless, and no one at Admiral level uses it. Instead, I think most people use the 3-bar setup with some variation of this:
This view works fine for me for the most part, but I do have a few gripes with it. First, I don't like how it randomly rearranges itself whenever I switch ships. And secondly, I wish it had more buttons. This is because I use both letters and numbers in my hotkey assignments.
In WoW, my toolbars were arranged into grids that looked like this:
The right-hand grid was for the shift key. So, my method in STO would require an absolute minimum of 4 rows with 12 buttons each, which is also what a standard keyboard provides. (If you didn't want to use shift keys, you could recreate the entire keyboard on the grid, although you'd have a hard time reaching stuff on the right hand side.)
Unfortunately, Star Trek Online does not allow that many buttons, so I've had to settle for this:
①②③④⑤⑥ - - ⃝⃝⃝⃝
ⓆⓌⓇⓉⓎⓊ - - ⃝⃝⃝⃝
ⒶⒼⓍⒸⓋⒷ - - ⃝⃝⃝⃝
This gets the job done, but it's really squished and compressed. It is difficult to organize the buttons and arrange them in an intuitive way. Basically, it just feels unpolished.
My main recommendation is they need to add a 4th row. Even if you don't want to use a layout like mine, it would still be useful for sticking weapons icons, consumables and stuff up there.