i never tried to change between dx9 and 11 in parallels or crossover/whisky since i didn't know that was possible, so i was using whatever is default. that said i tried messing with all of the wine settings and it didn't seem to make a difference. i even messed with stuff like esync and msync (or whatever they were).
DS2 comes in both DX9 and DX11 flavours. The latter should work better with d3dmetal and is more comparable to what proton is doing.