As you know, some combat items like the Toxic Blowpipe and the Dragonhunter Crossbow was nerfed: All stats has drained to 50% low, that sucks!, but the mechanics is the same. Killing vorkath will not be the same, but if you don't have the correct setup, you can start using low level weapons like the mentioned up here, you have to watch some guide, in the top of this post you will found a complete guide to know about all of Vorkath, methods and killing information, mechanics, tricks, etc. Good luck killing Vorkath ;)
PD: This guide was possible thanks the Youtube user AsukaYen OSRS.