It's really odd to me that in s5 the canon doesn't really utilize the fact that Martin is also an avatar. He got tossed into the Lonely, got marked by it, got his own domain in the eyepocalypse, but that was it! The rest of the time he's just hiking through the Fearscape. Feels like wasted potential to me.
Especially since this fact could be used for further jmart bonding. Sharing their experiences of feeding the Fears etc. But the narrative made Martin completely unaffected by his avatarhood, just so he could be that oh so necessary anchor for Jon's humanity. They should've both gotten a bit more monstrous. It would've made them worse but also infinitely more delicious.