I've been following this thread on the official EU wow forums for a few days and it has garnered the attention of quite a lot of people ( sadly no such thread exists on the US forums, not sure if people are aware).
( https://eu.battle.net/forums/en/wow/topic/17622573467 ).
Basically the thread speaks of how blizzard secretly baked automatic pvp ilvl scaling into the game not just for low lvl vs cap but for max level chars fighting each other as well.
To summarize what the thread is about for those of you who are too lazy to read the original thread, ilvl and secondary stats are meaningless in terms of damage/healing output vs other players.
Blizzard has implemented a system that regulates damage dealt/received by players so that any ilvl difference is automatically adjusted to be equal to that of the opponent and vice versa.
An example of this would be that a level 120 with 350 ilvl hitting another level 120 with 300 ilvl for lets say 50k damage, would see 50k damage on their screen but the opposing player would receive an adjusted version of that damage ( equal to the adjusted ilvl ) and would probably see a number closer to 30k ~ on their screen.
Furthermore, a lot of things have been tested by the people in the thread to see how can removing gear or wearing lower ilvl gear impact your character, and a lot of seemingly useless/several tiers old gear seems to be showing advantages over wearing BFA gear.
This might puzzle a lot of people hearing this for the first time, but in short, downranking some gear for items dropped several expansions ago will yield higher damage values than wearing high ilvl BFA gear in pvp content ( wpvp/bgs/arenas).
Old items with 3x sockets seem to be working to empower characters even further by boosting stats on old ilvl pieces to skyrocket values after adjustments, what is also interesting is that old weapons and items that used to provide CC benefits were being tested and were working up until blizz's hotfixed very recently ( weapons that provided a chance to stun targets for example ).
If anyone has any doubts about what I'm saying here, I highly advise you to visit the thread that I linked above and see the ample amount of proof/data that was given there.
With this system, blizzard has basically nullified gear for pvp and erased all incentives for pvp gearing from the game, this is both infuriating and baffling at the same time as this is an mmo and incentives for gearing is the fundamental core of this game.