After I first picked up my Goldwing, I felt the same that it could stay on longer to give anyone behind me plenty of time to know I'm turning. Now, I just hit the button a second time as I approach the turn.
Yes it is speed related and if stopped waiting to turn it will flash all of 15 times. I like to turn on the signal a full block before I turn so I will just have to get into the habit of turning it on and on and on and on.
Dirtdobber I wish it had VOX also. I also wish you could turn the NAV on while moving. I don't care and it makes sense that all the other buttons deactivate but the "on" button for the NAV should have been on the handle bar controls.