I've had thoughts like this before, but wanted to ask...
What effect might there have been had Crossbows become much more prevalent then they did, and easier to use?
EDIT: I decided to expand on the why I had for asking this. I've often wondered if it might have been possible to use some later gunpowder weapon tactics with crossbows, especially if they reached a point where they were just as easy to use and employed in enough numbers.