As of now I feel like this weapons is not as good as it could be. It only explodes gems, heals and gain armor, barriers itself and silences the first troop. It can be a bit better with the right class, like titan, for extra barrier, extra explodes and immunity to death mark and such.
I feel this weapons would really benefit from an additional 1-3 troops summon (very often it is the only troop left in a team and it has 3 empty slots so it kind of makes sense to summon troops there), a random transform of the enemy team (toad maybe?) and perhaps a chance to devour 1-3 enemies to speed up the time it takes to reach 1000 hp / armor and also it can provide a way to increase its attack (which is now completely missing).
The main issue right now is that only few teams can beat it and the rest will just have to quit the game because the crown will not have the damage to destroy it, just buff itself to 1000 armor and hp and stay there. I feel with these changes it will be able to wipe most teams there are and as a bonus there is no longer a waiting time or a need to quit the game (which is an awesome gameplay feature).
Or as an alternative you could at least remove the silence and explode. That could also be a good path to take I suppose.