No. Why? 1) We have assets that benefit form a falling dollar (FXB, EWW, LPL, CAJ, E, SLV, PPLT, XOP, USO, FXY, GDX). So those can go up much further/faster than the dollar declines. And 2) cash is beneficial when invested to average down. Those averaging downs turbo-charge your returns and is much greater of a positive gain than the negative slide of the dollar.
Warren Buffett has $147 billion sitting in cash right now and he’s not a bit worried about it, for the above reasons.