It isn't the fact that it doesn't automatically send it that is the problem. I couldn't even select the message and choose to send it as a text without changing the option (not sure if I can now that it is changed, as I haven't had a message fail again).
Ah, gotcha -- I recall doing a tap-and-hold on a message in iOS6 which allowed me to send as text. Haven't had one fail yet to test it on 7.