you have missed out on 1 point on your skill sequence. other than that, good build. yes i would suggest getting some early game items and perhaps playing him as a caster until later in game when you can get higher AD items

with hextech i mean hexdrinker

I have tried this and it fails hard. Before you have your Bloodthirster you are litterly in 50% of the game and u only get the phantom at the very end. U will have no more than 150 ish AD from 50% on and before that just your basic. I recommend using a much cheaper early game AD boost. Boots + pickaxe, tiamat, last whisper, hextech and brutalizer, than if game goes on u can upgrade those to maw of malm and ghostblade. U will have 280is Ad, all the perks from the items above and both a strong early, mid and late game (1-5 min, 5-8 min and 8-15 min)