I don't mind loot boxes in a sense I hardly feel interested on what is inside it. If I get that nice Witch Mercy skin, cool, if not, I'll play with the basic one, no problem. Most of the time I feel I get the full experience with or without loot boxes.
However, it's clear some development resources were syphoned to make the boxes and it's content, resources which could be perhaps be used to do, you know... more content.
The idea is the loot boxes PAY for it's content which would otherwise not exist. My issue isnt even with the time and manpower needed to create the content, but the creative effort which is diverted to create ways to make me spend money instead of focusing on the gameplay.
Still, most games are good enough with or without loot boxes and I'm glad I'm not one of those whales who feel they need to have every skin in the game to be happy.