This will probably be my final update, since I found some extra useful information.
I found an old database for 4.3.4, that has the correct base physical damage values for each version of the trinket.
LFR: 8028 - 12044
Normal: 9063 - 13594
Heroic: 10229 - 15345
Also I noticed something else, the Bone-Link Fetish on this server is actually slightly undertuned, here is some proof:
I got a picture of Bajheera's Bone-Link Fetish(LFR), he was a retail player during Cataclysm, and I got a link to the video if need be. The tooltip says it does 22346 damage, his current AP is 17768. (His Bone-Link: https://i.imgur.com/uLpvMZe.jpg) (His AP: https://i.imgur.com/vUVyOuu.jpg) -- Now I could be 1 - 3 damage off, since the picture is very rough, but I see 2234x, either 22346 or 22343. But I am 100% certain it says 22340+ at least.
Now here it is on my character in-game, where I tried to get the same AP with buffs; Slighty lower than his AP: https://i.imgur.com/sxlN6Tn.jpg, Slightly higer than his AP: https://i.imgur.com/vLM342t.jpg
Important:
I feel like you guys should be able to enable the normal and heroic version for the other classes again, since there's nothing wrong with the trinket, and since this is how it was intended and how it was on retail. Those reports also seem to be incorrect, based on all my previous posts and this one, if anything it is underperforming by a slight %.
If you guys want a specific formula as close to retail as I can get it, I found a reference point on wowhead, and another source:
"Damage is 9063-13594 base plus 67.5% of your AP as physical damage" https://www.wowhead.com/item=77210/b...etish#comments, Sabotage101. There is also various other sources confirming this is the correct scaling for the normal trinket: https://myfriendtimmy.wordpress.com/...unholy-in-4-3/
I also found a post on mmo-champion: https://www.mmo-champion.com/threads...519&viewfull=1, Shaiandra Post #267 - This was posted during the time Cataclysm was the main expansion on retail, so it is accurate.
"Raid Finder version needs ~1.6722 AP to increase its damage (min and max) by 1.
Normal version takes ~1.4814 AP to increase its damage by 1.
Heroic version takes ~1.3123 AP to increase its damage by 1."
Normal
Now that we have this information, we can easily compare it to the value found by most sources, and what we have here, let's start with the normal version.
(1/1.4814=0.675), this means it increases by 67.5% of your AP, that ligns up with the information found.
LFR
Let's try it with Bajheera's trinket on the LFR one.
(1/1.6722=0.598) 59.8%
(17768*0.598=10625), (10625+12044=22669) This is slightly off, but it is closer than where it is at the moment.
If we take both found values for the tooltip and divide then multiply on the % increasement found, we get 57.9% of AP, which gives 22346 as a result, now this is much closer to what was shown in the video, and therefor i suggest using this.
Heroic
I will simply do what I have done earlier.
(1/1.3123=0.762) 76.2%, now this value has also ligned up with a few sites I found on google by searching "Bone-Link Fetish "76%" attack power scaling", so other sources seem to agree with this being 76% too, so I would take it as that.
Results:
LFR: 8028 - 12044 + 57.9% AP (Since all the other answers are correct so far. This would be the original formula, according to Shaiandra's research: 8028 - 12044 + 59.8% AP)
Normal: 9063 - 13594 + 67.5% AP
Heroic: 10229 - 15345 + 76.2% AP
Note: I would still propose enabling it for every other class in the game at the moment, since the trinket in the game already works fine, the calculation is slighty off, in a way that makes it do less damage than it did on retail, as reflected earlier in this post and my other posts. Since if you want to use these calculations (from retail) the damage will increase anyways, might as well enable it now imo. This can be seen by my last post, the calculation ingame has 76.18% AP scaling + 12791 Damage, for the Heroic version, the retail one had 76.2% AP scaling + 15345 damage. This also nullifies all the reports from players saying it's damage is wrong (if they meant it does too much damage), i.e. what I meant earlier with the reports not being correct. Anyways, hopefully this is helpful.
Incase you don't use damage ranges for the trinket, the formulas would be:
LFR: 12044 + 59.8% AP
Normal: 13594 + 67.5% AP
Heroic: 15345 + 76.2% AP
These formulas should be as accurate as they get, with the information we have available @Deathreaverx
