I think the only major issue of note there is that such a change either nerfs Demonslayer set or forces it to play Grasp of the Dead (which it did originally), depending on whether +1 is applied to Chillwhisper or Grasp of the Dead. Right now, Demonslayer can play Mythical Contagion or Scarab Shell too. (+1 BS summon to Demonslayer is also a possible resolution here.)
On a related note, Scarab Shell bleed BS would suffer, but that might be alright(?) (see Bleeding Witch Hunter (with Crate kill video)). On the other hand, I think the most interesting part of extra BS summon is extra DoT stacking, and it’d be a shame to lose it unnecessarily.