I'll add another voice in general favor of the UI change, with one kinda glaring caveat.
I have bad eyes. I have to use URM's textbox replacement feature for a large number of games that won't give me an opacity slider, just to read the text. Most devs don't have a clue how to present text in a sufficiently readable format on top of backgrounds of many different colors/brightness levels, and then ALSO forget to give us an opacity slider or other text controls. So having these controls available is very nice.
My caveat: both disabled and currently-selected buttons are
very difficult to read, with white text on a light color button (and a very thin dark outline, in the case of "Idioma").
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Both the "Idioma" and "Español" buttons here are extremely hard for me to read, as are the greyed-out buttons for other languages (I can't even see what they say on this screenshot). If the background is dark, the text needs to be much lighter, or have a thicker light-colored border, and vice versa. The other top menu buttons are great, as is "English" in the language select, but the others are all bad.