How does the current version not work?

What Kevan said

The current version does not work the way it was originally intended and makes the spell a lot worse as spells like doom cloud and burn can easily be triggered by it. See the results for duel 9.

So it’s really a case of whether you think the effects of the Burn damage on neighbors and of Doom Cloud should cause the Wizard casting either of those to suffer the effects if another Wizard affected by those spells cast Synergy.

I like the targeted approach, so from me.

I like the Burn interaction.