Shadowverse

Arcus has the following problems: firstly, he needs a free turn to be played. He does nothing with 7 mana, which means he needs an evolve; you can't just throw him out there. Secondly, there's the follower problem. You need a lot of low-mana followers for him to have the desired effect, otherwise, everything will just go into trades. The more such followers you have, the weaker you are in the late game, especially when Ectar rotates. Possible solutions: you need a card with enhance or accelerate that can be played either at the beginning of the game to have some effect on the board or just for value, or in the late game. Alternatively, you could have some overpowered low-cost card that synergizes with him. The effect of Arcus also manifests in the fact that after him, your board control will likely disappear because the ghosts vanish at the end of the turn. Therefore, low-mana cards that summon something to the board are desirable, just so you don't end up with nothing against your opponent's board. Of the current options, the skeleton with Mighty Hand looks relatively good, but the problem is that it doesn't synergize with Arcus at all. Therefore, to make Arcus viable, you need more low-cost cards with an effect on the board without the need for an evolve, and on fanfare, rather than like the new gold card from the mini-expansion.