Yeah.. I'd so love it if you could charge without throwing pilums or throwing them without charging. I'd also like it if not every unit that isn't a hoplite has them.

Also yes, they're great at causing friendly fire deaths, like really great. The way you want to send the Hastati first and Principes second, the Hastati are probably going to take something like 10-30% casualties from getting spears thrown in their backs. They might even shield the enemy from the majority of the 'volley'.