Frankly, I'd be quite happy if Broodlord just became an actual useful card in his own right. First off, get rid of Unique. He's just A lord, not THE lord, and being unique completely goes against the swarmer concept. Coupled with that, give him stats and abilities that are balanced with his cost and morale, completely irrespective of his deckbuilding ability. The deckbuilding ability is self balanced and should cost nothing, resource wise. The positive of ignoring purity is more than balanced by the restriction of no non-insectoid cards. Even a modest bump to 9/9 or 10/10 would make him useful on the battlefield. Alternately, giving him a version of Matriarch or Kung-Ji's ability would add viability. Something like "when deployed, all insectoids heal 1 damage at the end of the turn" or "all insectoids in the support zone heal 3 damage at the end of the turn."
I was really excited at the idea of a swarmer deck, finally. But the reality as it stands is quite disappointing. I too am sure there will be more insectoid cards coming. The Great Hive is just too obvious of a Location idea, and there are plenty of artifacts that could flesh them out as a meta-faction even without resorting to insectoid ability cards. But we'll be waiting 3 or more months at a minimum until such cards come out. A couple small tweaks to the insectoids we have now would go a long way to bridging that gap.