If anything, EMs just need a slight adjustment to make them more useful, but really.. they're not too bad as is.

As for dropping them to get more of another kind.. there is already a better chance you'll get a CM than other missiles.. while you're at it, might as well get rid of nukes too :P </sarcasm>.

Overall, I don't think we'll see an option to get rid of missiles any time soon (read as EVER), unless you want to fire them off at someone.

If you have too many missiles, you're not warring hard enough!