BC Before boots is bad. PD without I.E. is bad 3 BT is bad. IE last is bad.

I can't say I like the idea of stacking damage runes on ANY character. While I can see the general meaning behind it, (considering he's an auto attack hero) I think arp runes and atk spd runes would much more fit the slots. I have to agree with the SS's though, they're my favorite too. Another thing is, if you die with this build, you lose a good 30% life steal and 120 atk dmg when you come back. Another thing, I think IE is a pretty big must for Twitch, and getting it last just doesn't set well with me at all. I find rushing BC okay, but I generally get an IE, BoM, and 1 bloodthirster before getting it. While I can see you're trying to make items like Frozen Mallet and others with health bonuses that Twitch usually needs to stay alive, I don't think LS will make up for it, especially against those heavy bursters like Malzahar that will supress you. Also, Xin Zhao will absolutely tear you apart in the time that his knock up gives.

I know you have to be fed, i got these items very quickly each game usually between 20-30 min I'm already completely stacked and the i see what your saying with the oracles but the games i play they would need a buy an oracles every 4-7 minutes because of how much i starve them
Also with the "Personally i like AS over ARP but thats just me good guide" comment - i see how you would see as over arp but the thing in because of the stealth effect, if you used this items from this guide, you should come out with 2.5 attack speed

I see two problems with this build, your mana mastery and your items in general. Twitch's base mana is 180+35/level, so getting an extra 3.75% doesnt seem like its worth taking expanded mind on twitch. You dont grab any extra mana items, so the most he'll ever get is about 30 extra mana at level 18. The second problem i see is that this build heavily relies on being fed early to be able to afford the Black Cleaver, Phantom Dancer, 3 Bloodthirsters, and an Infinity Edge. That's alot of cash, even if you sell your boots of mobility to help pay for IE. It would just take one tank or burst nuke to grab oracle's for this entire build to crumble because shutting down a twitch is very easy. I also prefer ARP over AD marks, because I prefer more early game damage against squishies.

Personaly i like AS over ARP but thats just me good guide