So what you are going to want to add is monsters and synapse. A Tervigon and a Hive Tyrant are great places to start with that. If you get the Tyrant, take wings. If you get the Tervigon, invest in making him a troop choice. Trygon Primes are also a great way to get some synapse but at the same time not sacrifice assault power.
What I mean by that, is if you take a Tervigon and roll doubles on your first turn, he is borderline useless. Can't do a whole lot in combat, but he can supply synapse. Now with the Trygon Prime, you get the same synapse, you can Deep Strike that synapse, and if you position him right, he can run in and do some heavy damage. Give him regeneration and you have a big mean bug ready to dish out some pain. Quite hefty in points, but he can pull his weight.
I would not recommend another Carnifex. You would be better served with a Harpy or Crone. A few extra points, but they will definitely take shots away from your swarm as they march up the field.
Since you have a large horde, Venomthropes will be your best friends in supplying 5+ cover to them.
Another thing you are lacking is anti-tank. You have a carnifex and he has a venom cannon, but with his crappy BS and save on 3+ he isn't too likely to fulfill the role you need him to. I would recommend Either some Hive Guard, Zoanthropes, Crone, or Harpy. A Harpy can be upgraded with the same gun as the Carnifex, but is a flying monstrous creature, and can also drop spore mines. The Crone has Haywire missiles and S8 vector strike, pretty awesome. Zoans are the best thing you can have for anti-tank if you can get them into range. Hive Guard got nerffed due to their lowered BS, but since they now straight up ignore cover they can be good if you roll half decent.
Some issues I have with your list itself. Everything is armor save 5+ outside of the Warriors and Carnifex, not good. If you want this set up you will NEED a Venomthrope or two. Lack of anti-tank, as mentioned above. Then there are the Devourers on the Termagaunts. They are great weapons, and in that many numbers they can dish out some pain, but with how easy they die it is not really worth putting that many points into them. Also, toxin sacs are a much better investment on the Hormagaunts rather than Adrenal Glands.