Given the current role of the warhound isn't working (anti-mech), why not make it a generalist as with the goliath?
Give it a weak main attack, the railgun, but supplement it with other, not OP, but not nerfed to hell skills. This railgun attack hits only ground, but the warhound can be refit, for a cost, to have an (one only, and it can't be changed later) additional weapon. This upgrade would be per warhound, not for the army as a whole.
The weapon refit ideas I was thinking, though they can be anything else, really, are haywire missiles for anti-mech, napalm cannon for anti-bio, gattling cannon for anti-air, and perhaps an EMP rocket for psionic or energy-wielding opponents (this would deal damage solely to energy).
These attacks would function like haywire did: they occur alongside the regular railgun attack.