Add the following after the last paragraph of the Synapse Creature special rule:
Models with Instinctive Behavior (Feed) gain +1 WS while within Synapse Range.
Models with Insinctive Behavior (Hunt) gain +1 BS while within Synapse Range.
Models with Instinctive Behavior (Lurk) gain +1 to their cover save (if they have one) while within Synapse Range.
This tweak would give creatures a bit of a boon while within synapse with their respective functionality (shooting bugs get better at shooting, assault bugs get better at stabbing, sneaky bugs get sneakier). Besides going nicely with the #6 results on the Instinctive Behavior tables, I think it would also reflect how in the background creatures under the control of synapse creatures fight more akin to soldiers and less like ravenous beasts.
Overall Effects:
Thoughts?