Josh is correct and I updated the errata document accordingly. It can be viewed as stronger than Shield Bash at low Circles, but then that starts to change at higher Circles. Shield Bash gains access to the Shield Drive knack, and can benefit from Waterfall Slam in addition to follow-up attacks with Momentum Attack, Second Attack, etc. Which are arguably more powerful because you can immediately capitalize on your now knocked down opponent.
Having spells that remain relevant over the course of a career means sometimes things aren't perfectly equivalent at all times. It also represents a risk v. reward. This payoff is good, but isn't guaranteed and the caster probably isn't in a position to exploit the advantage they created, while penalties associated with other spells are part of the effect. This includes situations where due to shifting initiative, the target may jump up without suffering an attack.
Where Invoke Leopard's Pounce is intended to shine is against flying opponents and those who aren't as physically robust. Against targets with high Knockdown, it's not nearly as useful. Comparing it to the Elemental Spear series neglects the versatility of having up to five different effects on hand when spell matrices are limited. The odds of having something appropriate for the situation, if not ideal, is very good. And one of them is an in-combat healing effect.
So, it's a very good spell in the right situations, but still represents an opportunity cost. In other situations, it's probably just damage that doesn't take the caster out of harm's way very well. It does promote teamwork and that's a good thing.
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