Chorus plugin in itself needs a mix knob. Some problems that I run into are:
1) Can't automate chorus effect smoothly from 0 to 100% for a buildup.
2) Let's consider the workaround i.e splitter mode. For some reason, the volume fader control under each branch in the splitter isn't automatable?!
3) Adding another mixtool just for this effect means that 3 plugins have been used just for automating a chorus section for a buildup...when the chorus plugin could just have a mix knob. Please fix this in the next update asap.