Hmmm, that's interesting, I re-read how that works, and, you're right. Mawlocs could easily be doing good work on lots of things like broadsides and such. They are one of the few things that can do damage BEFORE interceptor kicks in, which gives them an edge against Tau, which, as I'm looking at this, seems to be the worst possible opponent for Nids (mostly because of the availability of ignores cover and high-strength shooting as well as loads of nasty rapid fire). Mawloc popping up underneath two broadsides has a real shot at taking them both out in one go. That's significant.
I think that, with that in mind, that the HS slot will be the new Elite slot of this dex. Too much good stuff in the 3 slots.