'/' key works as 'enter' + '/'
To type commands, you have to hit 'enter' and then '/' and then the command. I don't think the '/' key has another function, so making the '/' key bring up chat and put a '/' makes sense.
Good idea — it’s also used when dragging stacks, but should be possible to figure out which one should be performed.
You should also be able to set a custom macro to the chat window. :)