The "lucy spam" is fine. The people that complain about it, like everything else in the game are the ones that dont understand it. High damage for little charge? my arse - just watch how fast you run out of ammo doing it....
The lucy is an interesting gun. Rubbish in the hands of an idiot who at best will spam down a long corridor hitting nothing, and at worst blast fully charged shots into team mates. Absolutely lethal in the hands of a good player who understands when to use each variation on its firing mechanisms.
However, no matter who is using it, its very expensive and has a habit of burning through ammo, especially if you dont have a battery.