Exchange one guant squad and the hormies for more genestealers with
EC. More staying power in shooting and assualts. Hormies got even more nerfed in 5th thanks to counter assault, thier low toughness, 6+ armour save, and fearless units taking wounds for losing assaults even if they outnumber. Shooting wise thier low toughness means they take more wounds and thier low armour means they are flamer fodder. Plus if a dakkafex gets drawn into the assualt, your opponent directs his attacks at the guants/hormies and you carni gets left taking wounds.
Might consider
EC for your Flyrant and Dakka tyrant as they tend to get close to the enemy and draw lots of shooting fire.
Strangle (boom) fexes as heavies options aren't my personal favorites. You trade a decent ranged weapon option that would complement your
BS for only 1
CC attack. Seams a waste for a fex that will spend most of the game shooting its
BS, not running towards
CC.
Anyways good luck