I would agree only if there was a confirmation.
A part of me doesn't want this though. You can't make corrections to search terms right now, and this would just create another hurdle that would make that a possibility. I mean before when search terms were treated as one string we didn't need it, but now that you can include multiple search words, it becomes more portant to be able to make accurate modifications to the search field and that would require use of the backspace and delete buttons.
I think it would be easy if you can custom map option commands as an alternate. It could be under Advanced controls where you can choose a list of extra controls that don't really fit the normal hotkey configuration abd you can set custom hotkeys for them. That way if you wanted to delete a selected beatmap, or bring up the add to collection, you can just go to Advanced controls section under menu options and set it to whatever key you want.
I also was thinking about the possibility of using the number keys when the options are displayed. I tried this the other day and it didn't work. I thought that because the options were numbered we would be able to hit that number to select that option and it didn't work. It would require an extra keypress to implement it this way. (One to open Beatmap options and another to select delete map)
If I were dev for the game, I would use the number keys to represent the different options available in all the menus. On the osu! screen 1 would select Play Mode, 2 would be Edit mode, 3 would be Options. In the menu, no options present, 1 would be mode, 2 would be mods, 3 would be Beatmap Selection options/ Within each option field, I would have numbered representations for the options or tab could be used. My programming style and preference is more focused on convenience while peppy is focused on simplicity, and compactness of the feature. I would really prefer more diverse settings and methods to navigate in the game.