And how exactly would your "icon-view" "make" the brick icons if the add-on creators can't? Would they even have control over what their category icons looks like?
Since not every add-on maker will be obliged to give a stuff about this, no. But there's room for interpretation. Since rarely 2 add-ons use the same category, add-on makers that care more could make their own icons for their categories. And
if someone makes such a category as well, in general sense, it would either be a extension of that category (in which case, it would require the original pack, in which case, it would not require the user to input in a special icon), and otherwise, it could simply be a different category if they both have icons. I'm saying simply because I am maybe trusting too much on how would reworking the tabs work.
Whoever makes the add-on would loving make the loving icons for the loving indexed bricks (putting emphasis on loving because I repeated this for the third loving time now).