Improve Essencia's Spell

The week of Dragon’s Claw has reminded us how annoying it is that Essencia’s spell does literally nothing in most circumstances. We want Essencia in our Dragon teams for the 50% starting mana boost, but otherwise the troop slot is completely wasted. The spell should be modified so it does something useful when the team is full.

I suggest the following change to the spell:
Summon a Dragon Spirit and explode 10 Gems. If there was already a Dragon Spirit in my team, summon another Dragon Spirit.

This change would make the spell always useful for mana generation, even when no troops have died yet, which fits much better with the trait that speeds up the team. However, it tempers the summons aspect to keep the spell from being overpowered for the mana cost. It also retains the aspect of the spell being improved if there is already a Dragon Spirit in play. Basically, it would summon only one Dragon Spirit unless you already have one and there are two open slots. I think it would play much better this way.