I did some testing with several classes across all 3 realms.
Here are some observations i made with the personalized loot, being obvious or not, but before that some clarification.
(observations, not critique or promotion)
Imbue points =! Utility.
The Value of Utility is a weighted rating of the bonuses a piece of gear can provide (armor, jewelry, etc.)
The bonuses are granted by filling up the room, the imbue points provide.
More imbue points can result in higher bonuses, which can result in higher utility ratings.
gruenesschaf wrote: Quality has nothing to do with mob level and is random.
Rogs have 2 "levels", one the visible one that determines the AF and dps and proc levels, that's in 5 level steps + the last level 51 step. Then there is the imbue point level, that's the same as the mob level. However, for weapons and armor pieces the imbue point level is capped at 45.
A level 51 crafted weapon has 28 imbue points at 99% quality, 32 at 100%. An accessory, e. g. ring, rog dropped by a level 51 mob with 99% quality has stats that sum up to 28 imbue points or 32 points if it's 100% quality. A 100% rog dropped by a level 90 mob (does not exist) would have stats that sum up to 65 imbue points. Again, armor and weapon rogs are capped to level 45 crafted items for the imbue points.
Imbue points are, as grunes already explained, tied to the level (mob / armor / weapon) and the quality of the item itself (which is random).
As an example a Lvl 51 Armor piece with 100% quality has 32 Imbue points.
As a crafter you can overcharge these items to 37,5 imbue points, however that is obviously not an option with a ROG drop. (But there are other ways*, more to that later )
So in general, 32 imbue points for 100% quality items at lvl51 (drop or not)
This is the step where the bonuses are determined/applied, which for drops is obviously random, but it has rule set as to how its applied:
gruenesschaf wrote: The imbue points just are, there are no modifiers aside from quality and mob level (and the weapon / armor cap). The selected class just determines the whitelisted stats (and weapon / armor type).
The stat distribution is simply picking a whitelisted stat randomly and then randomly picking an amount of imbue points to use for that stat. That is then repeated until all imbue points have been used up.
Ending the clarification here and starting with the observations.
As most probably already know, 37,5 imbue items can as high as 80 util, but can be also just as low as 60~ or even lower, depending on what bonuses are put into them.
A big factor in these high util ratings is the amount and values of the +skills on the item. (4 skill+4 skill+4 skill+4 skill = 80 util) <> (9 resis+ 9 resis+ 9 resis+ 44 HP = 65 util)
While spellcrafted Gear is limited to 4 slots, ROG items are not. Afaik there is no limit on how many slots they can have**.
The available imbue points for a ROG drop are, as already explained by gruenes, tied to the Lvl of the mob, which is fix, and the quality, which is var, but for the sake of simplicity is just assume all drops are 100%.
Here are some estimates:
Lvl 51 - 32 Imbue points
Lvl 55 - 35 Imbue points
Lvl 60 - 40 Imbue points
Lvl 65 - 44 Imbue points
Lvl 70 - 48 Imbue points
Lvl 75 - 52 Imbue points
Note: Only jewelry ROG, as Armor and Weapon ROG are capped at (Level 45) 28 Imbue points.
If i am right or wrong about these, may or may be not helpful for some, but it's not really that important, or the point of me trying to make.
The important part is how the bonus stat distribution is handled for every class.
Because there is a difference.
As gruenes already explained, every class has a whitelist as to what bonus may be applied to an ROG upon creation, and which not.
Examples: (leaving out HP+Resists out as they are the same for all classes)
General Caster and support:
Stats - Str, Con, Dex, Qui, Acuity stat for the class (Intelligence, piety etc.), Power
Skills - All Magic (regardless, a +skill Magic on a ROG is always "+all Magic" )
= 6 Stats + 1 Skill
General Heavy Tank (light Tank)
Stats - Str, Con, Dex, Qui
Skills - All Melee (regardless, a +skill Melee on a ROG is always "+all Melee" ), Parry, Shield, (+ All DW)
= 4 Stats + 3 Skills (4 skills)
General Hybrid
Stats - Str, Con, Dex, Qui, Acuity stat for the class (Intelligence, piety etc.), Power
Skills - All Melee, Parry, Shield, All Magic
= 6 stats + 4 Skills
Nightshade/Ranger - has not a stat that increases by +acuity, and +power is not whitelisted for them
= 4 Stats + 5 Skills
Hunter - has not a stat that increases by +acuity, and +power is not whitelisted for them
= 4 Stats + 4 Skills
Skald/Minstrel/Valewalker
= 6 stats + 3 Skills
The moment a ROG get generated, the "whitelist" of bonuses a class can have are used to determine which bonuses can get applied.
"
The stat distribution is simply picking a whitelisted stat randomly and then randomly picking an amount of imbue points to use for that stat. That is then repeated until all imbue points have been used up."
For a caster only 1 form of +skill can be applied, while for a Hybrid 4 could be on that item, while both could have +6 stats.
The sequence as to which bonus is applied first and subsequent is completely random (delve is sorted, it's not the applied sequence)
I do believe that Skills like Crush/Hammer/Body Magic etc. can be picked randomly, but they convert only once into a +all Magic/Melee, and all corresponding skills get delisted right after for subsequent applications.
Imbue points will be filled if possible: If nothing else besides +1HP would fit anymore, then it will get +1HP (unless +HP was already on the item).
Then there is the Util Rating as mentioned at the beginning.
Skill > Resists > Hits/Stats > Power; from higher to lower is the order of how utility is weighted.
The more +skills and +resists you have on a ROG, the higher the Util Rating will be, while the same imbue points filled with Hits/stats/power would result in a way lower Util rating; again...even though the same amount of Imbue points were used in both cases.
The imbue costs though are kinda different:
Skill > Resists/Power > HP/Stats
Which also tells us that you won't get a high Util ROG if you have +Power on it, or even very decent Util with higher values of +power. As they use up the same amount of imbue points like Resists do, but are much less weighted/value/worth in terms of Util Rating than Resists are.
One can argue about this being true or not, but in general it would be adviceable to have +skill and +resists on ROGs (high cost / high value), and +Stats and +HP on the SC Gear (low cost) for 3 reasons:
1. High Util jewelry is not only worth more plat, but also more desirable in general. Simple.
2. +Skill on gear is limited to +1 All, and can't go further. Which means it would have to be the specific +skill line (+hammer/LW/Thrust/etc.), if higher values are needed. Also, it may have to be replaced if Builds change.
3. SC is limited to 4 slots and (at most) 37,5 imbue points. Armor ROGs are even worse at even 28 Imbue points. Depending on the Class, this can be a very limited space to operate.
Here come in the "whitelisted" Bonuses of the different classes mentioned earlier into play.
The maximum potential Utility of a Caster ROG, can never be at the maximum potential Utility of Tank ROG.
Yes, Casters don't even need high Util jewelry to max out their temps, compared to a Melee. I know that.
Again, this is an observation, i'm not judging it, but it's a matter of fact.
Feel free to correct me if i typed something wrong. Put this together with several notes flying around.
* Gemcrafting is a thing. Most "profitable" Drops are ROGs with high Imbue points and with as many slots as possible.
Many slots --> many low values --> cheap/easy to raise.
** The amount of slots a ROG can have is kinda limited by the whitelisted bonuses a class can have.
Technically a caster ROG could have 17 slots (5x base stats+hp+power+9xresists+1skill)
A Hybrid could have 20 slots (5x base stats+hp+power+9xresists+4skill)
gruenesschaf