The Coming Bloodbath

I work at a top NYC firm. I am paid very well and the quality of work I get is outstanding. My problem is there is not enough of it! have raised this with the partners who simply say that it has been a below average year but that, hopefully, something will come along by the end of the year. Should I leave now before a bloodbath? Even if I survive that, ought not my professional development dictate that I move to another firm?