A world scaling increase system yes, an increase in drop rates, maybe, scaling loot definitely not.
Players are going to turn up the difficulty and than yell and scream it is too hard, than when we point out they can just turn down the difficulty they will yell and scream it is not fair others get more loot from he same kills and ignore entirely the fact there is a difficulty slider.
Why will this happen? LFR is why. Players join LFR and say it is too easy, say they want better loot, than complain when we tell them to join raids. Players turn on warmode and than complain they are being ganked and how it is not fair, than complain when we tell them to turn off warmode and say it is not fair those with warmode get more.
A bad player will yell and scream that the harder difficulty is too hard, it needs to be made easy, the loot needs to be improved and it’s JUST NOT FAIR!!!
Why do you think we have 4 raid difficulties? Normal was too hard by admission of more, they made it easier, than hardcore raiders said it was too easy, so they made heroic. Than normal raiders complained heroic was too easy, they made it easier, more complaints, LFR, more complaints, mythic.
Complaints made normal and heroic dungeons, further complaints paved the way to M+, people STILL complain, mythic raiding is too hard, M15 is too hard, LFR is too easy.
A bad player will complain endlessly about everything that they cannot do because they think they are the best there is and don’t realise, maybe your skill is limiting you to what difficulty content you can play.
Knowing Blizzard though, if enough yell and scream about it, it will come into play, than we will have 12 difficulty levels and players complaining about unfair loot not realising it’s just their own skill stopping them getting the same loot.