I do agree with this, 360sec is a hell of a long time to wait till you can send another message. I don't use pm's that much but when I have done, it can be pretty frustrating, specially if you are trying to resolve an issue.
David, will you respond to this thread, as far as I am aware it will have no other startling side effects and is just a matter of changing the default and would only take a few minutes, reading through it appears that the moderators are also in favour of this.
If you are worried about spamming in private messages, then I can understand that, but considering it is a lot quicker to spam in the public message board, and it gets a lot more attention, where there is no waiting time between posting, it seems that the easier option is to spam the message board as opposed to private messaging.
Also in regards to this, we have a lot more control over the private messages, the ability to ignore users, block them from sending messages, or just very simply deleting them.
Can we have some feedback on this?