It would be worth the cost if the goal were to make Magic Arena the most realistic simulation of paper Magic possible, but with the goal being to make Arena the best new and intermediate player experience possible, changing to a chess clock would be a horrible move (although there should be some changes to the timer system, even with the goal of Arena in mind, with the biggest being that the timer should stop during animations that you can't play through)
Itll be Druid of the Cowl way too often to be that excited, though its clearly nice when you actually stick a big creature on the board
Gains 300 ATK each time another monster's effect is activated, while the ATK of this card is less than 4000
Now, weve seen something like this before in New Phyrexias Living Weapon, but thats a mechanic very much tied to New Phyrexia (or at least the color black)
1 Foil-etched Mystical Archive uncommon In this slot, you will always get one of the 18 Mystical Archive uncommons in a foil-etched treatment