I think it's a little unfair to think a online multiplayer game of this size could avoid many of those problems.
While I deleted my post, I feel like you aren't taking into account what I DIDN'T list.
It isn't like listed pushing Atheon over the edge and shaking my head at them not thinking of putting in something that prevents it. I mean, they should've, but like you said, they can't account for everything either, which is why certain things were left out.
Low drop rates, extremely powerful weapons and a lot of things on paper just sound bad and could've easily been prevented. Especially since so many of the things I listed were the "end game" content and what people would be playing for the majority of their time with Destiny.
Some problems like forever 29 for example could be seen in advance if you put enough forethought into it
Not as much as you think. In fact, forever 29 became a thing largely due to the lack of exotic boots. Every combination besides missing boots offered a path to level 30, which was largely the issue.
the thorn meta
If you fully read my now deleted post you would've saw that I even admitted that they likely couldn't have seen the Thorn meta. In fact, I mostly listed it because of how long they took to fix it.
luck in the chamber snipers
Following the changes to Last Round?
maybe even the black hammer
Black Hammer was pretty obvious.
really don't present themselves until you hand the game over to thousands of people.
Like I said and even admitted in my original post, Thorn is acceptable, but the others aren't.
After they addressed the issues with the Spear and Last Round the idea of Luck in the Chamber should've been obvious.
Black Hammer is fairly similar. You create a gun that has high impact and essentially unlimited ammo, assuming you can hit an enemies critical spot, with the added bonus of it not taking up your exotic slot. It's pretty telling that not only was the Black Hammer nerfed, they made the nerfed version an exotic called Black Spindle.
No matter the size of the QA staff, there are just some things that they aren't going to find... So there's gonna be things that fall through the cracks and expecting any video game company to make no mistakes whatsoever is just being ignorant to how big multiplayer games work these days.
I think the disconnect is what is falling through the cracks.
Take the Vex Mythoclast. First off, this isn't some random gun that for whatever reason was poorly balanced. It is the special exotic you have a chance of getting for beating the games hardest original content. When the community got their hands on it and cried out for a nerf, Bungie thought it was appropriate to reduce its damage by 34 percent. This is a massive issue in balance and shouldn't happen for such a prominent gun.
Another example is Skolas. It wasn't like the flaws in this fight were hidden. Almost anyone who gave it an honest go would immediately see that the fight was deeply flawed. The same goes for "fixing" Atheon's teleport, something that had frequent and common problems, to the point where it didn't need to be in the hands of thousands to see something was wrong.
Even the drop rate, reward scale and so forth made obvious problems. Like is it really wrong to question a companies thought process when they make the rarest tier of engram have something like a 1 percent drop rate and then proceed to have it decode into a less valuable item 70 percent of the time?
I mean, I get where you're coming from, but even if you remove those three examples, there are still plenty more where a little more thought would've prevented them.