It's pretty important to lock out the 'alphanumeric' keys while you're on the radio.
Imagine if my landing gear were assigned to the 'e' key when I typed on the radio. Right now it's good that it shuts off key commands while I'm typing on the radio.
Good suggestion that anything that is assigned to a 'non alphanumeric' key should be available while you're typing in the radio buffer (that covers all the folks who still have the clipboard mapped to [esc])
Mind you, I get around this by having a button on my throttle mapped to the clipboard.
Personally, I'd love it if the '/' key could change what channel I'm transmitting while the text buffer is open. How many times have you started typing a message only to realize you're typing on the wrong channel?
Be nice that if you hit '/', started typing and then hit [shift]'/' it'd switch your text to the country chan.
~Lemur