Might be good for realism, but think about it... How many lucy shots hit out of ten when some alien really tries to attack you without getting hit? Those good goon and mara players (of course if aliens don't have s3+tyrants yet..) are your worst nightmare when carrying lucy.
Don't balance the game for those with lowest skill.
I'm not talking about realism (in fact, not showing any effect is probably the most realistic option), I talk about skill. Proper feedback is what allows better players to use their skills. If some guy in a BS enters a corner with the lucy already charged there is no way to know when he shot last time, so theres no chance to make the decission between dodging or attacking. Being able to make the right decission in combat is the best definition I know of skill, but the information is needed.
(BTW, ok about maras, but goons hard to kill if you have a luci?, you just need 1 shot, and they are big and slow targets. Ok, you can't chase them, but if they attack you they are dead)
As Paradox very well mentioned, you can make this decission as human when finding a goon. And it is extremely useful. I just miss the same thing with luci carriers, cause, atm, the only thing I can do when I find a guy with lucy is running away until he fires the first shot.