all world scaling give a bad feeling that your efforts/ progress is being invalidated.
It also gives a false impression of how effective your character should be/ feel in group content. a mob scaled way down because of your spec will leave you feeling nerfed in other content of supposedly similar difficulty.
now, there are ways to make it feel better and scaling has a place but scaling should always stop at level. scaling to your ilvl negates the point of getting gear. doing it wrong could make scenarios where deleting your gear is a power increase. because power isn’t numbers. its how much effort it takes to succeed. 2 hits with no gear and 2 hits with gear is no difference.
instanced content, especially solo instance content can benefit from scaling based on spec or at least based on roll, but if its scaling based on a role it should not be scaling to an ilvl.
one way to sort of balance a scaling mob is to consider gear quality. imagine a player with a specific gear quality at that level should have a similar number of hits across all levels assuming gear is appropriate for that level. so if a Epic geared character did battle with the same mob they should feel powerful compared to a green geared player fighting the same mob.
at max level world mobs should be scaled to a specific difficulty and stay there. they should at no point scale up but could scale down IF a lower level player needed to interact with the mob by design. in this leveling scenario the mob should still be fairly close to its intended power level at 59
but in any case, i would rather that damage be better tuned so that mob scaling to spec wouldn’t even be considered a thing that may be desired.
so lets put the roles on a scale where Heals tank and dps sit.
Baseline mobs should hit like they are fighting a healer in green gear
Mobs should be expected to last as long as if they are fighting a tank in green gear
Now with that, DPS do 1.5x the damage of tank single target
a heals does 1.25x the damage of a tank single target
in this way, the mobs remain the same and the classes baseline is what gets tuned up or down.
Mobs could be scaled up in difficulty by raising the expectation of the quality of the gear.
later game areas, could expect a baseline ilvl. “tuned around being ilvl 233” for example.
but over all that gets very complicated. its almost easier to just test that its doable with all classes with a certain gear level. some classes and specs will enevidably have an easier time but challenging world content will naturally encourage grouping up to do the content. and if the quests expect that to be the case, the “suggested 3 players” quests should show up more often for areas where the content is intended to be vastly more difficult unless you have “end game gear” maybe the mobs expect heroic gear to solo but can still be done if a group tackles the challenge. or players are able to out play the mob.
now to that end, strong mobs should be like those Rares that have a few deadly but telegraphed attacks. your fine if you avoid the big hits. MoP has a number of these.
but instead of rares, the could be the more difficult world content normal mobs.