When you use the sorting options of a table, the columns which can be sorted will get a sorting indicator in their column head. Currently, these are arrows.
The arrows are (in my opinion) rather thin, which makes them harder to read. I would much rather have different/thicker arrows here.

Even better would be to have the option of specifying custom sorting indicators, perhaps by adding an additional slot type to the tables.
I would really like to use the sorting indicators which are in font awesome (for which we already have a Pro license). The fa indicators are little black triangles, and they are very well known with most users, and also much easier to read than the thin arrows in a table.