Has the Hive Tyrant Scything Talos & Bone Sword+Lash Whip or 2 pairs of S.Talons? With it you will hit almost everything in the game at 3+ and if 2xST, reroll 1 & 2 results, with only a pair you reroll only the 1s, but the whip is good vs DE and Eldar and high Initiative opponents. The only thing is that together with Old Adversary the whole is a bit redundant, so you can well give the Tyrant one shooting weapon! And is also very important the combination of Psi-Power you choose (usually the best are Paroxysm and Psychic Leech). As a MC, the Tyrant would well use its shooting wp + 1 Shooting Psi-Power!
Also, with your actual combination, I think you will make Outflank the Termagants or the Tervigon (Hive Commander ability) and this can be a problem in two ways: 1 the Tervigon will not spawn if it Outflanks (actually starting its turn outside the table) so it will be alone; 2 the Termagants will Outflank but they can be easely out of Sinaptic Range. So, maybe, you can choose another suicide Unit of Troop to Outflank, like Hormagaunts, drop one squad of Genestealers, drop the TS and AG for the Gargoyles, and give some advance to the Trygon (see how many point you save, but usually upgrade to Trygon Prime to give more SYnapse range in DS actions).
Keep the Termagants around the Tervigon to benefit from TS and AG, and Outflank with a strong unit of Hormagaunts that have also Fleet and are more long reaching than Termagants!
