+1 Spells you cast this turn have “As long as this spell is on the stack, players can’t cast spells or activate abilities that aren’t mana abilities.”
-2 Destroy target land. Its controller adds three mana in any combination of colors to his or her mana pool.
-5 Put three 6/1 red and green Elemental creature tokens with trample and haste onto the battlefield. Exile them at the beginning of the next end step.
Were you trying to avoid mentioning split second in the first ability? It'd read a lot less wordy if you could just mention the ability. It might be simpler to just say "Spells you cast this turn can't be countered" (although I do appreciate split second is more useful than that).
I can't see why the ultimate makes you sac the tokens at EOT, either. Sarkhan Vol didn't do that, and he was one of the least-played planeswalkers in constructed. Is it just so they can more closely match Ball Lightning/Groundbreaker?
I do think you've done very well at finding effects that work in both colours in this whole cycle, though.
Yea, I didn't want to reference Split Second on the card itself just because the keyword isn't evergreen and thus far nonevergreen mechanics haven't appeared on Planeswalkers. And I originally considered making it just "Cannot be countered" but then his +1 would effectively only be useful against blue decks. The tokens were indeed sac'ed at EOT to resemble Ball Lightning/Groundbreaker. To make it more effective there could be more than 3 tokens, but thats 18 points of board dominance by itself with trample.