Plat 4, the BIG times... xD Sorry. It's just that... every time I see someone try to bring up elo as an excuse to dismiss someone else's opinion on the boards it's someone in gold or low plat, which is just funny.
"His shrukens DO do absolutely no damage early game."
That's not remotely true. Also you got the damage wrong. The damage you listed is for the second shuriken if he hits a target with both shurikens, which is half the max damage of one shuriken. Single shurikens do 60% of their max damage to targets after the first target they hit.
So for example if you hit for full damage at lvl 3 you do 172.5 + 150% bonus AD before armor and armor pen factor in with just Qs hitting but using W for the extra one. At lvl 1 you do either 75 + 100% bonus AD or you do 45 + 60% bonus AD if you hit a minion first. Also his Q goes up 40 base damage per rank, that's a lot.
A typical lvl 3 double hit but going through minions on both does 103.5 + 90% bonus AD.
"Currently, all assassin runs full armor pen runes due to last whisperer nerfs, but let's just say with long sword start and runes you have 20 bonus AD."
You should test out AD runes. I don't know the math on it to be certain one way or the other but I know that Zed has a 100% bonus AD, an 80% bonus AD, and a 100% bonus AD scaling on his abilities AND gets 5-25% extra bonus AD from his W's passive. It also helps his wave clear where as armor pen doesn't.
"Zed cannot auto attack an adc late game to death"
I mean not just auto attacks yeah... But he should be able to get an auto or two in at least. His R and W and Youmuu's active certainly make it possible. His passive makes it worth while.
"And his spells (unless extremely fed) will not 100-0 an adc, he's forced to rely on his secondary ult proc, and often times he cannot use his W to aid his burst, rather, he's forced to use it to escape because most people now camp his ult shadow as well as his current location."
His spells + 1 auto can kill any adc if both players are at reasonable levels of gold mid and late game. Plus that's assuming the adc is full hp and Zed has 0 help hitting them. Your situation basically involves Zed trying to ult and burst down the adc while they sit in the middle of their team and Zed is all alone. Yeah if you do that you're bad and gonna die without killing them, duh.
"if the enemy adc just buys GA on top of mercurial he will have basically completely invalidated Zed."
No, that just means Zed should probably ult someone else. Unless of course you can proc their GA fast enough and then your team can win the fight enough while GA revives them to be worth while. Teams do not consist of 4 tanks and an adc. Also the adc had to put all that gold into those 2 items and get very little damage out of that gold. That alone is a big help to your team.
If the enemy team is 2 tanks, a mage with zhonya's, an adc with GA+mercurial scim, and a support you don't feel is worth ulting to kill... then your choice is simple. Go split push!
"As for the low elo thing, in all honesty it's very true. Most people on this board have no idea how the game works, and try and make a post explaining something with civility and they spam downvote you simply because their biased opinion doesn't compare to facts."
Yes most players don't understand the game very well. Most people in plat fall into that same category. ;) Ignore the downvotes, they don't change the validity of what anyone says. But remember that some people in bronze understand the game better than some people in diamond. Understanding the game doesn't automatically make you good at it and vise versa. Right now some of the best pro LoL casters are in silver, and some of the worst (when it comes to game knowledge at least) are in diamond.
