The Custom Hero Grid is a fantastic feature included in the Summer Scrub, but it is very barebones at the moment and lacks some basic quality of life features that would make managing it clean and easy. My number one suggestion is to add alignment tools to the grid's editing functions. Currently it takes a great deal of effort to ensure categories are sized exactly as desired. This would not be such a big deal if you layered them and simply matched the corners to make the categories identical, but this isn't always possible, which leads me to my second suggestion; bring the currently selected category to the front (or include a toggle that turns this behavior on and off) so that I can edit categories that would otherwise be stuck underneath another.

Some small issues I noticed while using the grid editor; dragging a hero portrait to an empty category won't place the hero into the category, it instead deletes the portrait. You need at least one portrait in the receiving category in order to click and drag portraits between categories. Sometimes when dragging portraits around, if placing a hero into a category that's seemingly full onto the right most side, there are some wonky graphical effects as it tries to preview the category before dropping the portrait in. When going to resize a category, the editor has a habit of shrinking the box once you move the mouse, which offsets your mouse from the actual category corner and makes the already difficult task of resizing accurately even more arduous.