>>28675412That sort of ability would let you autowin against Dragons, and would really dampen up Mewtwo and Rayquaza. But they'd probably ruin its attack to "balance" it out.
Which is the other half of the problem right now. The way they weight energy costs and damage is almost completely random. You have cards like Greninja and Garchomp competing with garbage Stage 2s like SS Chandelure or any Luxray. And there's also this weird aversion to printing complex effects.
Light Dragonite in today's meta would probably just have 40 more HP and its attack would be [G][L][C][C] with 20 more damage.