I think one of the underlying "reasons" for level-scaling is a lack of enemy mobs available at each level. It takes a looong time to 3-D model, and animate each individual mob, along with any equipment variations, etc.
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This way an "Orc" is basically an Orc. But an Orc with firey armor and a lightning-tinged greatsword is something to be more cautious about.
I'm okay with "reskins" and "elites" and new variations and such. I also liked the way MGS5 did this where the enemies reacted to your strategies. For example, if you're getting a lot of headshots, then they're more likely to start wearing helmets. There is a logical explanation as to why the existing enemies have gotten more powerful.
Never played it. Haha. Looks like they've used it as their obligatory RPG cardgame. Looks pretty cool, though still just a minigame?