Slash commands are slow, and make things confusing. Not very many servers only have one bot. Many have multiple bots. Some have multiple bots with a lot of common commands. So while suggestions SEEM like a good idea, it will just confuse the users. That is what help commands are for, and documentation as well.
If privacy is the motivation behind slash commands, then I have exciting news! Admins can simply create a channel and restrict the ability to see message history. Maybe even make an admin only channel for certain commands to be used. Bots can DM the responses if the content is considered sensitive. The bots can quickly delete issued commands for the same reason after responding.
Tuduh! Problem solved! All you got to do now is enforce that kind of behavior for verified bots and commands that could reveal sensitive data. Maybe even implement a way for devs to mark commands as sensitive.