Here's a good way to bring Garruk back into the Magic Story, whether he's still a planeswalker or not: Bring him to Ikoria for a big hunt. Make Ikoria a hunter's world where hunting parties go for big game. Touch on legitimate hunting for sustenance vs hunting for sport vs poaching for profit. Garruk is supposed to be this big in-touch-with-nature-and-beasts but he's always portrayed as some stereotypical barbarian. If he's supposed to be some warrior-druid and planeswalker, then he definitely needs some way to show that. Let him get involved with Ikoria in some way and bring on the hunt!
