This card makes me want to leave the game... It's so annoying, it has to be limited. 800 permanent atk malus per monster is far too much. I know there are counters in the game, but you can't build a real competitive deck if you have to focus on countering a specifical card.
If they added main phase 2 to the game, this card wouldn't be as broken as it is now. Sure, you'd still have moments where your opponent uses this when you have one monster, but you wouldn't ever have to worry about having a field of 0 attack monster
The number of gems required to fully open the entire mini box (just in case it's in the last pack), is 4000 gems.
Unless you throw almost all of the "new player reward" gems into Servant of Kings, some players won't have enough gems to even get 1 copy of this SR card. They'll have to save up gems first over a long period of time, unless they spend some money to open more packs.
That got me thinking, if we have a meta full of monsters unaffected by destruction effect from Trap cards, this card would see more play compared to Mirror Force.
I remember when I saw this in Arc V and the way it was used was totally different from DL. After Yuya activated it to reduce a monsters AKT with 4k points, the monsters point returned to normal rather than go down to zero during the end phase