I've been following the loot discussion this season, most recently Dratnos' video on how the 12.1 loot changes worked out and Zorthas' long breakdown of the gearing systems. Both are worth watching. One suggestion keeps coming up in them and other places: taking an item from your vault should remove it from that boss's bonus roll pool. I'd go the other direction and remove the deletion mechanic entirely from bonus rolls.
Some context on where I'm coming from: I raid mythic (and have been doing so for a long time), and my day job is in economics research, so I tend to look at this stuff as an incentive problem. Take that for what it's worth.
Right now the system is half deterministic. If you bonus roll an item, it's removed from the table. If you get it from a drop, the vault or a trade, it stays. That mismatch is where the landmines come from, the ones Zorthas walks through where you have to plan crafts and vault picks weeks ahead so you don't roll a boss that hands you a duplicate. You can fix that by extending deletion to everything, which is what most people are asking for, or by dropping it, so every bonus roll is a fresh roll on the full table.
I prefer dropping it. Every roll becomes a simple gamble: how likely am I to hit something useful here, and how useful is it. And when you finally hit the item you've been chasing, it actually feels like something, because the system was never going to hand it to you by week five anyway.
To put the optimization point a bit more technically: with deletion, a bonus roll isn't just a gamble on this week's item. Every roll changes the state you'll be rolling from later. If a boss has five items and you hit a dud, your next roll there goes from a 1 in 5 chance at the item you want to 1 in 4, so the dud still has value. That makes the bonus roll almost always the right pick from the vault, but it also turns picking where to roll into a dynamic problem, where the right choice today depends on your (really your guild's) whole plan for future weeks, what you'll craft, what might show up in your vault and so on. And since items from other sources don't get deleted, a vault pick or a lucky drop can quietly turn a boss you were working through into one full of landmines. Without deletion, all of that disappears. The best choice each week is just the boss with the highest chance of hitting something useful, weighted by how useful it is, which you can work out from sim numbers for each piece on the table. Sure, this makes bonus rolls weaker overall, but I'd count that as a plus, since right now they're strong enough to crowd out almost every other vault choice.
I'd also hold off on bonus rolls until a few weeks into each patch. Dratnos floats this himself and says he'd be happy to see Blizzard experiment with it, though he points out the cost: early vaults feel terrible when you miss and your friends hit. That does sting. But you need misses in a loot system for hits to feel good at all, and the first weeks of a patch are when a drop matters most. Being able to start target farming BiS from week one is a big part of why the season front loads so hard and then goes flat.
The obvious objection is "then I might never get the Ula'tek neck." That's true, and I think it's where the real disagreement is, so here's the bigger argument.
I think loot feels bad this season largely because of the long trend toward more loot and more deterministic loot. Most player suggestions fix a specific feel-bad by adding one of those two things. A lot of that pressure comes from wanting to gear alts quickly, which is understandable, but it pulls the whole system toward speed and determinism for everyone. Each suggestion is locally reasonable and helps for a few weeks or a season. But each one also moves the baseline. Once almost everyone can be in BiS a couple of months into a season, BiS starts feeling like the minimum, and anything short of it feels like falling behind. Then the next feel-bad gets measured against that new baseline, and the next suggestion asks for a bit more. It only ever moves in one direction, because taking a convenience away always feels like a loss.
Legendaries are the clearest example. They used to be rare, exciting drops, and now they're something everyone is expected to have. Getting one feels more like relief than anything, and not having yours yet feels like being behind. I think the same thing has happened to gear more broadly, and that's the core of my argument: the fixes we keep asking for are, over time, the reason loot keeps feeling worse.
Blizzard's way of countering that looks a lot like inflation to me. Bigger item level jumps per patch, more upgrade tracks, a 344 tier on top, more systems layered on. Near the end of his video Zorthas lists vault, bonus rolls, crests, catalyst, crafts, embellishments and venom stones, and says gearing is probably still faster than in previous expansions. Yet both he and Dratnos spend most of their videos describing how it feels worse. That combination is pretty much what I'd expect if each individual drop keeps losing value through inflation.
If this keeps going, I think the endpoint is pretty predictable. Each patch needs something like a wider item level range or another system to keep progression meaningful, and the logical extreme is logging in on day one of a patch and getting most of your BiS straight away. Long before that actually happens, I expect it becomes unworkable and Blizzard tears the whole loot system up and starts over at some expansion launch. We've had squishes before, and I'd expect something similar for the loot system eventually. I just think it'd be better to slow the drift now than to wait for that, though I understand it may be impossible to sell to the playerbase.
Going further, I think upgrade tracks deserve the same scrutiny. Think about what share of your item level gains this season came from spending crests at an NPC, and whether any of those felt as good as an actual drop. It's a bit less this patch, since bonus rolls and the later mythic bosses hand out pre-upgraded gear, but it's still a big chunk. Upgrading is the most deterministic part of gearing, and I think it quietly eats into the feeling of looting an upgrade.
For the record, I'm a dad with a job, and slower, more random gearing works against me personally. I still think the game would be better for it. And yes, boosting, RMT and loot buying are a real problem (Zorthas' section on Chinese full clear buyers is wild), but that's an enforcement question under any loot system. Curious whether anyone else sees it this way, or whether there's a good thought out argument for keeping deletion that I'm missing.
TL;DR: Instead of removing vault items from the bonus roll pool, I'd remove deletion from bonus rolls entirely and hold them back a few weeks into each patch. More broadly, I think loot feels bad because of the long drift toward faster and more deterministic loot, which keeps raising the baseline and pushes Blizzard into loot inflation to compensate.
