Now that we can type in the name of the bus or plugin we’re trying to get to (which is so much better than it was before!), it would make a lot of sense to allow up/down arrow use.
If I have three busses; Drum Stem, Drum Parallel, and Drum Master, I can type in “drum” in the menu but then have to physically click on which I want; I can’t just use the down arrow to highlight the item in the search results and hit ‘enter’ to launch it. This would speed up everyone’s workflow immensely; you wouldn’t have to type and then go back to the mouse before selecting the bus/plugin - it would all happen from the keyboard.